Knight Online - http://knightonlineworld.com/
It's a great MMORPG.
It's a somewhat medieval magic type game.
Rogues, Priests, Warrios, Mages are the classes you can choose, then under each class there is a sub-class. Priest - Healer, Rogue - Assasin, Warrior - Attack/Defense/Berserk , Mage...