If you want to power-game things for when you someday hit 60, the hierarchy of shaman races is basically:
- Ogre (stun immunity is handy for soloing at high levels)
- Troll (regen is great, and they can use the JBB)
- Iksar (regen is great, but no JBB)
- Barbarian (no immunity, no regen)
But that being said, I picked a Barbarian myself and have no regrets because ...
- XP Penalty: Barbarians have the lowest XP penalty. I'm only level 57 after playing for more than a year: if I'd gone evil I'd be even lower right now.
- Jaundiced Bone Bracer: I use my JBB A LOT, and Iksar can't. 'nuff said.
- Kunark Cities: Almost all of the good dungeons in Kunark lower your faction with The Overthere. If you're an Ogre/Troll you have to choose between avoiding those dungeons, being KOS in your only Kunark town, or doing a lot of faction work.
- Old World Cities: This is less of a deal, but it's still nice to be able to sell/bank in Kaladim, Freeport, and various other places all over that evil races can't.
IMHO, the correct race for you is ... whatever seems the most fun. Seriously, this is a game, and none of the factors I just listed really matter
that much. Just do what appeals to you.