EQ2 can be very good fun if you have a group of players you reguarly play with, lots of interesting content which can keep you entertained for ages. Imho it's let down by the end game when you get to raiding but getting to the raiding level theres loads of decent stuff to do.
D&D Online is also a lot of fun, it's strange how I don't fel the urge to play it all the time (like i did with EQ2, WoW, EQ and UO) but when I do play it I always have a good time. I imagen with a core group for D&D it would be even better, some of the quests are amazeingly fun and 6 people could do nearly everything in the game.
Someone said Vanguard, totally diffrent game from WoW, EQ2, D&D (plus it's only in early beta) if you want a game with huge potential but hours and hours of work to get there then it looks good. it's hugly item based and is all geared towards the end game content of raiding and the like.