I would suggest a /Willpower brute or scrapper. Dark Armor isn't favored by many and costs A LOT of influence to build a decent one.
Why Willpower?
Willpower gets Quick Recovery. At level 2 you unlock Stamina(fitness pool). Quick recovery is a 30% end, while Stamina is only 25%. Any powerset you go with... It'll be a pain in the primary to burn any endurance.Primary - Scrapper
I would suggestPrimary - BruteMartial Arts - Good DPS, no down time.
Claws - Good DPS, low endurance costs, and fast animation
Dark Melee - Good Single Target damage. Has a Self Heal(Siphon Life), Damage bonus(soul drain), and +Endurance(Dark Consumption) - In dark Melee, there is a - tohit so this will be perfect combo with Regeneration, Electric Armor(One of the most rising Secondary for Scraps/brutes/tanks today!, Invuln(costly of endurance)
Fire Melee - Insane DPS, Does Damage over Time.
Spines - Insane DPS, Damage over Time.
Broad Sword - Extreme Single Target Damage.
I would suggestPretty much the same as a Scrapper.
Stone Melee - Very extreme single target damage. End Heavy.
**Note: You get quick Recovery at level 20.**
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Firstly, welcome back to the game!
Next, I don't have a full DM/Regen build to toss out, but those two sets should keep your endurance bar fairly full in the early game, especially up to 25. You have inherent Stamina which you should 3-slot with endurance modification SO's. In Regen, you'll have Quick Recovery. Take that and 3-slot it with endurance modification SO's. Dark Melee also has a trick in Dark Consumption that pulls endurance from enemies and gives it back to you. With all those, your endurance should never be a problem.
I've played several Regen Scrappers to 50, but never a Dark Melee one. The most endurance heavy one was a Broadsword/Regen who ran all the Leadership toggles and Focused Accuracy (this was long before Inventions). With just Stamina and QR, I never really had an endurance problem.
Hope this helps!
Main Character: Ice/Storm/Ice Controller (Justice, 1340 badges)
I have a very long-time DM/Regen character that existed long before IOs, so I'll try to share some experience. Warning, small book incoming. 
Both Willpower and Regen are excellent at low downtime, being good at filing back your blue and green bars rapidly. DM is a nice combination with either. In a world without fancy IO benefits, DM has been at times considered to be as strong as some entire Scrapper secondaries in terms of the survival benefits it offers you, so it's never a bad choice.
The biggest thing to remember with DM is that it is pretty single-target focused. Soul Drain and Dark Consumption are AoEs, but they have pretty large recharge times, so they are not "bread and butter" attacks. (They are very good buffs, though!) Shadow Maul is very nice in terms of the damage it does, but its area of effect is kind of small - it can take skill to get more than a couple of foes in its area. It's also vaguely dangerous to a Regen because it locks you into a long animation during which you can't heal. (I still take it on my builds, because, hey, it's better than no AoEs.)
The single-target thing is important to remember because it puts a limit on one of DM's big benefits in a non-IO world - the toHit debuff it applies to foes. You can't lay that on a lot of foes at a time, because you just can't attack that many at once.
The good news though is really Siphon Life. This power is almost silly good. Its one of your best damaging attacks and it also heals you. In a world with SOs, I recommend you focus on slotting it as an attack, as the base heal it gives you is decent even with no Heal enhancement. It may seem strange that something like this would be desirable with powesets that also heal you, but Regen does have times where all its clicks are recharging, and being able to get in another heal (while hurting your enemies) doesn't suck at all.
Basically, WP gets you HP back over time. Regen also gets you some HP back over time, but gets you big chunks of HP back in periodic bursts. Dark Melee can buy you time, which both secondaries will be able to use to refil your green bar.
In this vein, Touch of Fear is a pretty potent power in an SO build. IO'd DMs or those with less time-sensitive secondaries often skip it, but a couple of hits with it can disable a dangerous foe. In something like a fight with two bosses, this can make a huge difference in the incoming damage you need to heal back. If you can fit it in, I think it's worth considering.
Since I mentioned WP too, I want to cover the high-level differences in how WP and Regen play. If you already have this info, feel free to stop reading. 
WP is pretty obviously full of toggle and passive powers. The only click powers it has are Strength of Will and its self-rez. Pretty much, you fire up its toggles and go, and the only click you have to worry about being able to get to in a hurry is maybe SoW. WP can't get big chunks of HP back in a hurry, as it lacks a self-heal, but it tends to take a bit less damage than, say, Regen, as it has some damage resistance and some defense to help fend off attacks.
The more foes you have around a WP, the better it regens HP. This is a little at odds with DM's single-target focus, as the regen improvement in getting more foes around isn't likely to counteract the increase in damage you start taking. WP doesn't have a self heal, so adding Siphon Life is a pretty big deal to a WP.
Regen is very much about click powers. Getting those clicks back is the key to survival. Hasten is a Regen's friend, IMO. Reconstruction, Dull Pain and Moment of Glory are your go-to survival powers, with Instant Healing letting you enjoy occasional spurts of WP's regen at its best with your other click heals. Compared to WP, a Regen's HP suffer a much greater roller coaster ride. You need to have good reaction times to activate your clicks when you're in a tough fight.
In my opinion both WP and Regen are excellent sets that play very differently and therefore cater to different preferences. I like Regen, because careful attention to timing my power activations puts my survival in my own hands more so than passives with fixed stats do, which is something I enjoy. I think DM/Regen works nicely, though its probably not the most min/max thing you can build with Regen. (That's probably Katana/Regen.)
I hope this helps you, and you enjoy what you do build.
Blue
American Steele: 50 BS/Inv
Nightfall: 50 DDD
Sable Slayer: 50 DM/Rgn
Fortune's Shadow: 50 Dark/Psi
WinterStrike: 47 Ice/Dev
Quantum Well: 43 Inv/EM
Twilit Destiny: 43 MA/DA
Red
Shadowslip: 50 DDC
Final Rest: 50 MA/Rgn
Abyssal Frost: 50 Ice/Dark
Golden Ember: 50 SM/FA
Thanks for the info guys, it has helped quite a bit. I'll have a look at willpower too because it sounds quite interesting. I'll have a play around in the next week or so, trying out different stuff, seeing what I like (such as whether to go for more single-target-focussed or aoe-focus powers).
Any further advise on powersets which are light on endurance (primaries and secondaries) would be appreciated.
Edit: How is energy aura on a scrapper? I was having a play around on mids and saw that with just SOs I can get near soft-capped defense (40% S/L, capped energy, 43.6% cold, hot, 36.6% neg, 17% psionic with 3 targets in melee range (with these % not much lower with only 1 in range). Is the endurance recovery good on it? I saw energy drain and energize which look pretty good.
I have a dark/regen brute and it feels like cheating. In my mid 20s and I don't even have end reduction in my attacks yet because I don't need it. Brutes have the advantage with regen given the higher HP base, but I don't think scrapper would be that much worse.
I have a Dark/Regen Scrapper at 31, and he's pretty fun.
Of course, you could make a Dark Melee/Firey Aura Brute, a.k.a. the Buzzsaw...
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Hi guys. I started playing CoH when ftp started but then stopped after a couple of weeks due to school exams. I am looking to start up again. I am a free player, so I cannot use IOs and am stuck with whatever is available to free players (SOs only, I'm guessing). I am looking for a build that can kill well, has decent survivability and importantlyhas little downtime caused by a lack of endurance or health recovery. I played a few builds before, but all of them really chewed through the blue bar (I only played up to a max of level 25ish, though).
Without the IOs with the bonuses in endurance recovery, can this dark/regen build give be good damage, survivability and regen rates with only SOs? If so, could I get suggestions on which powers are must haves, which are skippable, etc. (Include stuff from power pools in here please).