I can't sleep, so here's my personal rundown of the whole sonic set. I've included different sections for PvE and PvP since some powers are good for one thing and not for another.
[u]Sonic Siphon[u]
PvE: Alright-ish. Doesn't stack, so you don't really need recharges. Provides a handy -25%ish resistance debuff to the person you put it on. I don't use it that much vs normal foes since the animation is so long, but I tend to use it on AVs/GMs since you have more time to stack -res then. I'd reccomend slotting this with two accuracy and maybe one recharge to get it perma.
PvP: Pretty much like above, I don't tend to use this very often since the animation is so long. I only use it in PvP when we're stacking -res on a stone tank or something similar, otherwise I'm usually too busy finding my next cage target/buffing to use it. Two accuracy and one/two recharges is the way to go for PvP slotting.
[u]Sonic Barrier[u]
PvE: You are dumb if you do not take this. Seriously. The sonic buffs are incredibly awesome, and basically one of the main reasons to take the set. Slap 3 damres in it and you're pretty much res-capping anyone after epic shields, and providing a pretty damn good resistance boost pre-epics.
PvP: As above, except more so. Put a couple of ranges in it for PvP, and an end reduction since buffing any team over 6 people puts a big strain on your end bar.
[u]Sonic Haven[u]
PvE: As above. This shield just buffs everything other than smash/lethal/toxic.
PvP: Exactly the same.
[u]Sonic Cage[u]
PvE: Useful for putting bosses out of fights while your team mop up the rest of the mob, although it's helpful to make a bind to let them know you've done it since the FX for this power are damn near invisible. VERY situational, you could probably leave this out of your PvE build if you really wanted, but I personally wouldn't. Slot with two acc and however many recharges you particulary feel like.
PvP: Where to start? This power can literally turn the tide of any battle. It's 100% unresistable, so you can cage scrappers, tankers etc in one hit as well as everything else. Slap it on the enemies main support character and watch the rest of the team fall apart. Slot with three accuracy and three recharges and the cage becomes permanent apart from the time it takes you to fire the animation. Don't PvP without this power.
[u]Disruption Field[u]
PvE: Handy to provide that extra bit of damage, since this provides a -15% resistance AoE field around whichever teammate you put this on. Be careful, though, since this will get you aggro if whatever you drop this on does not have a damage/taunt aura. I usually like to put this on tankers who are definitely running their taunt auras, or scrappers running powers like quills or death shroud. Put two endrdx in this power, since it can be quite end heavy when coupled with your other toggles.
PvP: I had trouble using this power in PvP because it only has a really short range. I found that even superjumping as high as I could would put me out of range of the person I had it on, so I dropped it from my build. It could be handy, though, in situations like base raids where everyone is likely to be less mobile and more close together. Two endrdx as above.
[u]Sonic Dispertion[u]
PvE: As with the single target buffs, you are dumb if you do not take this power. It provides a decent resistance boost to you and those around you, as well as protection from disorients, holds and immobilizes. Slot it with 3 damres and 3 endrdx.
PvP: As above pretty much.
[u]Sonic Repulsion[u]
PvE: Don't bother. All this power does is miss all the time until it uses all your endurance (which happens really fast) since it has an accuracy check and yet is unslottable for accuracy. I have never found a use for this, ever.
PvP: Waste of a power. Plain and simple. No, it doesn't work as stalker defence.
[u]Clarity[u]
PvE: Clear Mind with a different name. I would never expect an Empath to be without Clear Mind, so a sonic is no different. Slot it with one range.
PvP: Pretty much as above, except that it's better than CM because its animation is much much shorter. Slot with three recharges and three ranges for maximum stacking.
[u]Liquefy:[u]
PvE: No. Just no. It's basically a subpar version of ice slick, except it has a longer recharge. The hold element of it lasts like two seconds, and the tohitdebuff and defence debuff aren't even noticable.
PvP: Ahahahaha. Never take this power for PvP. People will just run out of the debuff, or they won't stand still for long enough for you to actually hit them with it in the first place.
And now onto the blasts. Sonic Blast is the ONLY blast set worth taking on a sonic defender, really, since the two sets synergize so well.
[u]Shriek[u]
PvE: Single target low-ish damage attack. You have to take this, but it's not that bad. If you're going to try and do damage, though, I wouldn't bother slotting this. I have it to stack -resistance on AVs, though, since it stacks with itself and so I've put two accuracy and three recharges in it.
PvP: Pretty much the same as sonic siphon except it has a smaller animation and stacks with itself. Two acc, three recharge.
[u]Scream[u]
PvE: A whole lotta dots. Pretty good damage, plus it lets you ninja kills from other people because it's DoT :P I have it for stacking -resistance with Shriek, so I have two accuracy and three recharges in it. If you're going for damage, put three damage in there instead of recharge and stick an endrdx on the end.
PvP: As above pretty much. With three recharges in both shriek and scream they cycle almost instantly and you can stack something stupid like -120% resistance on a single target - enough to reduce even a granite tank to his knees.
[u]Howl[u]
PvE: Average-ish damage cone. A nice attack if you get hit with fulcrum or something. Two acc, three recharge, one endrdx.
PvP: Single target is pretty much king in PvP, so I wouldn't bother with this power. Besides, sonics are generally meant for team builds so your blaster/scrappers should be doing the main bulk of the damage on your debuffed targets.
[u]Shockwave[u]
PvE: Gale with a different name, right down to having the same animation. It has a little more damage than gale, but apart from that it's about as useful. Take it if you like knockback. Personally I don't like KB enough to take this power.
PvP: As with Howl, it's not that great. Most sensible PvPers are running Acrobatics anyway, so this power is practically useless.
[u]Shout[u]
PvE: Short range, high damage attack like the description says. This attack actually does a fair bit of damage, but has a pretty long recharge so isn't that great for stacking -resistance. Two acc/three damage/one endrdx as standard.
PvP: Pretty much as above.
[u]Amplify[u]
PvE: Aim with a different name. Useful but not neccesary for PvE. Slot it with three recharges and as many tohit buffs as you can spare.
PvP: Basically required. Use this before your cage to damn-near guarantee a hit unless they've popped a whole ton of purples. Slot with three recharges and three tohit buffs.
[u]Sirens Song[u]
PvE: Cone Sleep with a pretty decent duration. If your team are careful, you can make any mob a walkover with this power. Slot it with two accuracy as standard, and then if you feel like it you could put a few recharges/sleep durations in it although the base recharge/duration is pretty good already.
PvP: Another cone, except this one has a stupidly long animation (the same as Decieve from illusion). It is a sleep, but it takes so long to fire that the blaster on your team could have probably killed the person you're trying to sleep before the animation is finished. I had this for a while, but found it pretty useless. Don't bother.
[u]Screech[u]
PvE: As useful as you'd expect any low-damage single target stun to be, really. As with Sirens Song, slap two accuracy in it and then recharges/durations to taste.
PvP: Bloody annoying. This is useful for knocking acrobatics off'f squishies so your team can bounce them around, and the range is nice too. Two acc, durations/recharges to taste.
[u]Dreadful Wail[u]
PvE: It's a nuke, but it's a defender nuke so the damage pretty much stinks. I used to use this after being hit with fulcrum shift, and I guess it was pretty good then. On its own, though, the damage is awful even though it makes a cool noise. It is an AoE -resistance and a stun though so that makes it a little more useful than other defender nukes. Having said that, it leaves you with 0 end. If you really have to have it, slot it with 1 acc 3 damage and 2 recharge and only use it after firing amplify.
PvP: Only really useful in a baseraid after you've had a load of +damage buffs dropped on you and you don't have anything else to do. So never, basically. If you do want to use it, slot it like you would for PvE. I wouldn't, though. Ever.
[u]Epic Powers[u]
Basically the psi epic is the only way to go for sonic/sonic defenders since power doesn't add anything new as your buffs aren't able to be powerboosted. TK is useful in both PvE and PvP, and the epic shield will take you to damn near the res cap when stacked with Sonic Dispertion. Dominate is a handy single target mez, although I don't use it that much in PvP, and Mass Hypnosis is useful to fling if you miss a few enemies with Sirens Song in PvE.
[u]Pool Powers[u]
Personally on my sonic I have Fitness (Swift, Hurdle, Stamina), Leaping (CJ, SJ, Acrobatics), Speed (Hasten, SS) and Concealment (Stealth, Grant Invis, Phase Shift). I'm all PvP built though, so you could probably take out Phase shift. Acrobatics is handy just for filling in the holes in Sonic Dispertion (although you're still vulnerable to sleeps). Hasten makes fun powers like Amplify come back up more often, although it will mess up your cage cycle in PvP (although if you use amplify at the same time this recharges as the cage drops on your target). Grant Invis is handy for putting on the squishies in your team to stop them from getting any extra aggro in PvE, and it drops debuff toggles on your team in PvP. Fitness is a must, seriously, since sonic is so end heavy. Don't bother with aid other, it takes up too much time where you could be doing something more useful. I never really found any of the other pools that hot either, since you don't have the endurance to run leadership toggles, or in fact any more toggles at all.
Holy cow. I might just repost this in guides, since I wrote so much :P
P.S. I just read through my post before posting and I forgot to say that sonic is awesome, so I'll do it now. Sonic is awesome.
. i'll even add a couple of 100ks for anything else. 