I've been a WoW addict. But I quit, and it was because friends helped me get out of my room more. So yeah, it helps to go out and have real-life fun.
I've tried other games: Gears of War, Fallout 3, Drakensang, to name a few. But never really got into them as much as WoW. It's like I play an hour, say I've had fun and do something else, something productive. I read a book, do homework (yeah, college rocks) and I'm going out. Just have to find the right girl for me.
My advice is, try the game, then see how you react to it. But it's not like a drug. MMO's are like drugs, singe players games (maybe with multipleasure... multiplayer option) aren't that addictive. At least not to me.