There is a way to sneak around the troll.

However, at the time, I did not know that and it took me several battles to get past this thing. While they are quicker than Giants, they do telegraph their attacks, so once you figure out the pattern, it is easier to dodge and smack. However, as you stated, the regen of them is fast enough that you can just scamper back a bit to avoid the attack, then press your attack.

Vegetable soup is the answer!

A weapon enchanted with fire (Trolls are weak to fire) and not giving it time to regenerate its health. And health potions.

Then again, if it's a Frost Troll, run fast in the other direction.

Essentially this.

I was on my way to High Hrothgar with a Fine Steel Sword and some clothing (not armor). A frost troll showed up. After a lengthy battle, I managed to slay it.

Hint - trolls hit slow. You can dodge their hits by walking backwards. That's how I got it.

I forgot to mention the fact that there is an enchanted Steel Warhammer named Trollbane

Try to dodge and flank them instead of just backing up or avoiding the hits. After playing many hours with my dual wielding, lightly armored Khajiit, I have to say that mobility is key. Run past them off to the side, even.

Come back around with a swing (or two, if you have quick enough weapons/perks), and power attack when able in order to stagger. The most reliable combo is two normal hits followed by a power attack; that will start and end the attack string very quickly.

If you're fond of axes, invest in the bleeding perk to counter their health regeneration. If you're using two handed weapons, swing just once before you power attack.

I remember getting nuked by my first Frost Troll...

I was at the point in the Thieves Guild to just after Karliah saves your life and you wake up outside of the dungeon that Mercer betrays you in. She starts a conversation explaining everything, and I notice that there's a Frost Troll only 30 feet away who is doing its angry-dance and she's oblivious that it's there...

(mind you the game had only been out for a week at this point, so I didn't know that I could cancel the conversation, kill the troll, and then pick up the conversation right where we left off...)

So, long story made short, she keeps me locked in conversation as the Troll beat me to death. I was so mad...

If you're an Orc-

Two-handed weapon + Berserker rage + power attacks = dead trolls all around

If not Orc-

Shield bash + shield bash + potion + shield bash + strafing = dead trolls all around

I also used the shield bash my first game when I was low level. It took me a while to figure it out but once you get the timing down it is very effective. I shield bash and then get an attack in while they are staggered. This playthrough I am a mage and it was fire all the way.

of course its juts going to take a ton of dodging and possibly reloading of saves.