All personal opinions, of course but I think these are the essential powers:
PvE:
Block of Ice
Ice Slick
Arctic Air
Jack Frost
Power Boost
Glacier
Ice Sword
Bitter Ice Blast
PvP:
Block of Ice
Ice Slick
Chilblain
Shiver
Arctic Air
Power Boost
Ice Blast
Ice Bolt
Bitter Ice Blast
Avoid:
Frostbite. I don't think I'm being too harsh when I say this power sucks for an ice dom. It doesn't do much good but it does negate Ice Slick, which is your main control power in PvE groups.
Everything else depends a lot on your playstyle. I've respecced my ice/ice twice and had all the powers from the secondary and all but Frostbite from the primary, and there are lots that are very nice but not must haves. Power choices and especially slots will be tight. If you want to do damage you need the melee attacks and the blasts will be great for building domination in PvP. I suggest not neglecting your secondary.
You will need Stamina, I suggest getting it at level 20. I also found that Aid Self helped a lot at mid levels.
Got to agree there 
All those PvE powers are the ones I've got but do have a few more :P Could post my build later if helps.
01 : Ice Bolt acc(01)
01 : Block of Ice acc(01) hlddur(3) hlddur(3) hlddur(5) recred(17) recred(37)
02 : Ice Sword acc(02) dam(15) dam(15) dam(17) recred(37)
04 : Ice Sword Circle acc(04) dam(5) dam(9) dam(9) endred(11) recred(11)
06 : Arctic Air endred(06) endred(7) endred(7)
08 : Hurdle jmp(08)
10 : Combat Jumping jmp(10)
12 : Ice Slick recred(12) recred(13) recred(13)
14 : Super Jump jmp(14)
16 : Health hel(16)
18 : Hasten recred(18) recred(19) recred(19)
20 : Stamina endrec(20) endrec(21) endrec(21)
22 : Power Boost recred(22) recred(23) recred(23)
24 : Frost Breath acc(24) dam(25) dam(25) dam(27) endred(40) recred(40)
26 : Glacier acc(26) acc(27) hlddur(29) hlddur(29) recred(31) recred(34)
28 : Chilling Embrace endred(28) endred(31) endred(31)
30 : Ice Blast acc(30)
32 : Jack Frost acc(32) dam(33) dam(33) dam(33) hlddur(34) hlddur(34)
35 : Greater Ice Sword acc(35) dam(36) dam(36) dam(36) recred(37)
38 : Bitter Ice Blast acc(38) dam(39) dam(39) dam(39) recred(40)
Is the build I run with, am pretty much just PvE so not sure if it would work PvP. Cant recommend AA enough though
Edit: Plan for extra post 40 slots is confuse in AA and slow in CE
"Well, they found my diary today.
They were appropriately appalled
at the discovery of the eight victims
They're now putting it all together.
Women wrapped in silk
with one leg missing
Eight legs, one body, silk,
spider, brilliant!"
hmm..... been fidling on the CoV/CoH Hero builder and i seem to be struggling a bit with power choices and slotting lol.
its pritty much a given that there will be acc and end reductions aplenty and seen as this is going to be a PvP build (to get revenge on all those evil controllers 
how i hate them *shakes fist*).
Anywho, heres my build plan. Please be nice lol
---------------------------------------------
Exported from Ver: 1.7.6.0 of the CoH_CoV Character Builder
---------------------------------------------
Name:
Level: 41
Archetype: Dominator
Primary: Ice Control
Secondary: Icy Assault
---------------------------------------------
01) --> Chilblain==> Acc(1)Acc(3)EndRdx(3)Rechg(33)
01) --> Ice Bolt==> Acc(1)Acc(5)EndRdx(5)Dmg(34)
02) --> Block of Ice==> Acc(2)Acc(7)EndRdx(7)Rechg(34)Hold(34)
04) --> Ice Sword==> Acc(4)Acc(9)EndRdx(9)Dmg(36)Dmg(37)Dmg(37)
06) --> Hover==> Fly(6)Fly(11)Fly(11)
08) --> Shiver==> Acc(8)Acc(13)EndRdx(13)Rechg(37)
10) --> Swift==> Run(10)
12) --> Ice Slick==> EndRdx(12)Rechg(15)Rechg(15)
14) --> Health==> Heal(14)Heal(17)
16) --> Fly==> Fly(16)Fly(17)
18) --> Power Boost==> Rechg(18)Rechg(19)Rechg(19)
20) --> Stamina==> EndMod(20)EndMod(21)EndMod(21)
22) --> Ice Blast==> Acc(22)Acc(23)EndRdx(23)Dmg(31)
24) --> Arctic Air==> EndRdx(24)EndRdx(25)EndRdx(25)
26) --> Glacier==> Acc(26)Acc(27)EndRdx(27)Hold(29)
28) --> Chilling Embrace==> EndRdx(28)EndRdx(29)
30) --> Frost Breath==> Acc(30)EndRdx(31)EndRdx(31)
32) --> Jack Frost==> Rechg(32)Rechg(33)EndRdx(33)
35) --> Greater Ice Sword==> Acc(35)Acc(36)EndRdx(36)Dmg(40)Dmg(40)Dmg(40)
38) --> Bitter Ice Blast==> Acc(38)Acc(39)EndRdx(39)Dmg(39)
---------------------------------------------
01) --> Power Slide==> Empty(1)
01) --> Sprint==> Empty(1)
01) --> Brawl==> Empty(1)
01) --> Domination==> Empty(1)
02) --> Rest==> Empty(2)
---------------------------------------------
I think you've gone a bit overboard with endurance reductions. You only have single target attacks so it won't be that bad once you get Stamina. Also slotting that little damage will probably cause you to spend much more endurance because you need to attack so much more. Go for mostly accuracy and damage for attacks and accuracy, mez and recharge for controls. Arctic Air needs the 3 endurance reductions but the second one in Chilling Embrace is probably better spent elsewhere. Seldom used powers like Glacier and Jack Frost don't need endurance reductions at all.
It's a good idea to slot lots of accuracy and endurance reductions at first and then shift some of the slots to damage when you get DOs and SOs. Cynic's build above has good PvE slotting, for PvP add one accuracy to each power. You might eventually want some recharges in the attacks so you can build Domination faster in PvP, but IMO it's most important to concentrate on PvE performance at first so you get your toon leveled up.
I would try to focus slotting a bit more - for example not more than 2 slots in chilblain, one slot in Health and pump up your attacks more with damage. I would try to get Hasten, maybe replace chilling embrace with hasten since you already have Shiver, AA and Frost Breath.
With the pet you might get more mileage from slotting ACC,Hold and/or Damage. It's quite rare that I need to re-summon mine before it's recharged, but it's a long way off for you anyway 
heres my updated slotting and powers, its not much differant but ive tried to take your advice :P lemme know whatcha think
---------------------------------------------
Exported from Ver: 1.7.6.0 of the CoH_CoV Character Builder
---------------------------------------------
Name: Koori
Level: 41
Archetype: Dominator
Primary: Ice Control
Secondary: Icy Assault
---------------------------------------------
01) --> Chilblain==> Acc(1)Acc(3)EndRdx(3)Rechg(33)
01) --> Ice Bolt==> Acc(1)Acc(5)EndRdx(5)Dmg(29)Dmg(34)
02) --> Block of Ice==> Acc(2)Acc(7)Hold(7)Rechg(34)Hold(34)
04) --> Ice Sword==> Acc(4)Acc(9)EndRdx(9)Dmg(36)Dmg(37)Dmg(37)
06) --> Hover==> Fly(6)Fly(11)Fly(11)
08) --> Shiver==> Acc(8)Acc(13)EndRdx(13)Rechg(17)Rechg(37)
10) --> Swift==> Run(10)
12) --> Ice Slick==> EndRdx(12)Rechg(15)Rechg(15)
14) --> Health==> Heal(14)
16) --> Fly==> Fly(16)Fly(17)
18) --> Ice Blast==> Acc(18)Acc(19)Dmg(19)Dmg(29)
20) --> Stamina==> EndMod(20)EndMod(21)EndMod(21)
22) --> Power Boost==> Rechg(22)Rechg(23)Rechg(23)
24) --> Arctic Air==> EndRdx(24)EndRdx(25)EndRdx(25)
26) --> Frost Breath==> Acc(26)Rechg(27)Rechg(27)
28) --> Chilling Embrace==> EndRdx(28)
30) --> Glacier==> Acc(30)Acc(31)Hold(31)Hold(31)
32) --> Jack Frost==> Acc(32)Dmg(33)Dmg(33)
35) --> Greater Ice Sword==> Acc(35)Acc(36)Dmg(36)Dmg(40)EndRdx(40)
38) --> Bitter Ice Blast==> Acc(38)Acc(39)Dmg(39)Dmg(39)EndRdx(40)
---------------------------------------------
01) --> Power Slide==> Empty(1)
01) --> Sprint==> Empty(1)
01) --> Brawl==> Empty(1)
01) --> Domination==> Empty(1)
02) --> Rest==> Empty(2)
---------------------------------------------
Why are you slotting Chillblain?
Why are you slotting Hover and Fly (I know it is nice to be fast, but I think you would do better fully slotting you attacks and key powers such as Frost Breath, Jack Frost and Glacier, and putting some confuse durations in AA). If you wnat to be fast go for Hasten and SS or CJ and SJ.
If you want to a lot of PvP you will probably want to include tactics.
I really should do something about this signature.
I agree with PRAF. Your core powers are not very well slotted, you need to concentrate on them before putting slots in things like Fly and Hover. Chillblain doesn't need any slots except for accuracy. Ice Slick needs 3 recharges, I wouldn't bother with the endurance reducer though.
I don't think Tactics offers enough benefit to warrant two power choices, though. I'd rather go for Medicine if I had powers to spare.
my biggest problem usually with making toons is my horrible tendancy to hamstring myself from the get go by making "themed" characters, and unfortunately medicine, from what ive seen of the animations, just doesnt fit with the Theme of Koori so hence will likely never get a look in :P
Regardless though i want to get the slotting right on this guy so i've taken everyones advice and mash it together best i can and come up with this:
---------------------------------------------
Exported from Ver: 1.7.6.0 of the CoH_CoV Character Builder
---------------------------------------------
Name:
Level: 41
Archetype: Dominator
Primary: Ice Control
Secondary: Icy Assault
---------------------------------------------
01) --> Block of Ice==> Acc(1)Acc(3)Hold(3)Hold(5)Hold(31)EndRdx(34)
01) --> Ice Bolt==> Acc(1)Acc(5)Dmg(7)Dmg(7)Dmg(17)
02) --> Ice Sword==> Acc(2)Acc(9)Dmg(9)Dmg(11)Dmg(11)
04) --> Chilblain==> Acc(4)Acc(13)
06) --> Combat Jumping==> Jump(6)
08) --> Shiver==> Acc(8)Acc(13)Rechg(15)EndRdx(37)
10) --> Swift==> Run(10)
12) --> Ice Slick==> Rechg(12)Rechg(15)Rechg(17)EndRdx(40)
14) --> Super Jump==> Jump(14)
16) --> Health==> Heal(16)Heal(34)
18) --> Power Boost==> Rechg(18)Rechg(19)Rechg(19)
20) --> Stamina==> EndMod(20)EndMod(21)EndMod(21)
22) --> Ice Blast==> Acc(22)Acc(23)Dmg(23)Dmg(27)Dmg(31)
24) --> Arctic Air==> EndRdx(24)EndRdx(25)EndRdx(25)
26) --> Glacier==> Acc(26)Acc(27)Hold(29)Hold(31)
28) --> Frost Breath==> Acc(28)EndRdx(29)Rechg(34)
30) --> Chilling Embrace==> EndRdx(30)
32) --> Jack Frost==> Acc(32)Acc(33)Dmg(33)Hold(33)
35) --> Greater Ice Sword==> Acc(35)Acc(36)Dmg(36)Dmg(36)Dmg(37)EndRdx(37)
38) --> Bitter Ice Blast==> Acc(38)Acc(39)Dmg(39)Dmg(39)Dmg(40)EndRdx(40)
---------------------------------------------
01) --> Power Slide==> Empty(1)
01) --> Sprint==> Empty(1)
01) --> Brawl==> Empty(1)
01) --> Domination==> Empty(1)
02) --> Rest==> Empty(2)
---------------------------------------------
Basically the endred are there because i cant really see how u wouldnt need at least one to last any kinda of time in a PvP brawl, (incidentally this build is for PvP ONLY and is what ill be gunning for after a respec) and ive only really put them in the powers that cost over 10 end to do.
Please be gentle with me lol as u have already no doubt worked out im not very experianced when it comes to slotting
I still don't see why you want 2 accs in chillblain but only 1 damage in Jack Frost, the best damage power you have. 
All Chillblain is good for is bringing down flyers, and you can always pop a yellow if you having trouble hitting in PvP.
You really nead some recharge reductions in BoI. Having hasten would help too, since in PvP you need to keep your target held then beat it to a pulp with melee attacks (If you use your ranged attacks you will run out of end before you can kill even a squshy). Using AA in PvP is a good way to run out of end in no time flat too, even slotted with 3 endrecs its still a hog.
I really should do something about this signature.
addendum then :P ill take one of the acc from chill and put it iin Jack as a damage
Do that, and slot BoI 2 acc, 2 hold, 2 recharge reduction. 
I really should do something about this signature.
lol will do
is there anything else your experianced eye can see that needs changing? id rather be told than stuble round in the builder makin the same ol' mistakes :P so long as theres an explination for why it needs to be the way it is so im learning lol
Only that PvPing with an Ice/Ice is hard work, but when you do win you leave your foes with a really suprised look!
Oh, and don't expect to ever use domination.
I really should do something about this signature.
Jack Frost has much higher acc than you do, might as well just put one in him and 3 damage
"Well, they found my diary today.
They were appropriately appalled
at the discovery of the eight victims
They're now putting it all together.
Women wrapped in silk
with one leg missing
Eight legs, one body, silk,
spider, brilliant!"
Heh, been on the test server yet PRAF68? Pretty easy to get Domination up there.
I havn't tried PvPing on test with a dominator no, but you are the first person not to say "I still can't get my domination bar full before I faceplant".
I really should do something about this signature.
Well it depends. If I can stay alive at all I'll get Domination up no problem. I don't pretend I didn't die a lot but I got kills too, even solo. If a spines scrapper decides to make it his goal to destroy me, I still have no chance. I'm not by any means good at pvp but I did fine kiting melee types, and with squishies is was a game of who mezzes whom first. No inspirations makes the game quite different. It may also have helped that the zones were crowded so I was often able to join in battles where I wasn't initially the primary target. Domination decays slowly so you can well do hit and run to build it.
Basically though, if you can be of any use at all in PvP you'll get Domination up pretty often too. All it takes is 10 attacks and firing off an /ice blast takes one second. I don't really see how it's that much worse than any other squishy anymore. I single-handedly killed scrappers yesterday, and it wasn't even that hard.
my toon is all built up and i have run him through the little tutorial bit (in a record 2 minutes
) and have my new power to select......
but tbh i have no idea what powers to take in the set or how to slot them!
help me out guys! i know i want to PvP so what secondaries should i be takin yadayada yada :P