LOTRO is pretty decent if you're a lord of the rings fan.
Vindictus is good
SWTOR is a must for starwars fans
D&D: neverwinter is also a good one to try.
all of these have features you have to pay for to unlock. LOTRO you have to buy 2 of the classes, and you only get 2 default class slots. And you have to pay a little for mounts. But the cool thing is you can earn the Emoney by completing in game challanges, so if you're really good at saving and really determined you really don't have to spend anything but time to get what you want.