None. I played WoW fairly consistently (first ~3 years as a hardcore raider) through about 2 months into Cata, but the casual weekend raid I played with fell apart, and fuck raidfinder. Tried to play MoP for a month but I just couldn't get over pandas, so I'm waiting for the next expansion.
Still, since I was in a top 10 guild for a long time, coming back to start all over again feels like Michael Jordan after he came back from retirement to play for the Wizards. My life situation is so different than when I started playing back when I was 18 that I can't play at the level that's required to be at the top, so I'd just kind of rather not play.