Actually, the main reason I didn't specify that much, is because I'm open to any MMO's, as long as they have an addictive storyline (that feeling of character and story progression), not falling into the usual quest-reward with no meaning.
Playability would be a close second priority, read as actually feeling a battle is dynamic, requiring strategic thinking / acting.
Casual gaming would be a third priority, as I won't have that much time, but I may have some day.
As for the theme, I don't actually mind if it's medieval, post-apocalyptic, zombies, cockroachs (?) whatever... If the game draws you in, I think I could fit in any role. I do like the stealth-type, like assasin, spy, or whatever.
Would that help in my request? :)