I love mmo games but they do not love me...
I played wow for 4 years, had an 85 DK, 85 Warrior, 85 Druid, 85 mage, 80 Paladin, 80 hunter, and a level 20 warlock... i had to quit!
I also played RIFT, AION, FF14, Warhammer, LOTRO, D&D online, Requiem Bloodymare (free), Forsaken World (free), Runes of Magic (free), league of Legends (free and amazing)
I would suggest either WoW (if you dont mind being consumed by its ever grasping addictiveness) or RIFT (amazing game, amazing graphics, people are just as elitist as they are in WoW but its still a good game to waste some time and do what MMO'ers love to do, progress)