World of Warcraft is quite addictive. It's similar to Diablo II, in that there is almost always something that you're doing that has an imminent reward. It also combines social interaction -- grouping is very helpful and fun -- and limited safe areas.
All in all, not a game you can play for five minutes or have in the background when you're doing something like folding laundry.
I've been playing with the Lounging Lurkers, a guild formed from the Lurker Lounge web site. It's a D2 analysis site, which appeals to me as both a D2 fan and a rules geek. So there's a degree of minor legend status associated with the folks in the guild, and it's quite fun to play with them.
On the other hand we have City of Heroes, the superhero MMORPG. I've been anticipating this for some time now, and since I pre-ordered, I'm guaranteed an invite to the beta by April 7th. So I'll want to be playing that.
And I can't keep up with one MMO, let alone two, what with the fulltime job and the kids and all.
Gee, nice problem to have -- which cool free game do I want to play? Of course, COH stops being free in a couple of weeks when it ships, but the first month is a sunk cost at this point.