I played World of Warcraft for the first year it was out, but had to drop it because it was taking over my life, just like everyone said. Since then, I've been pretty much MMO-free. Sure, I've poked my head into Age of Conan, and I tried out Champions Online a little. But all that was recreational use--sightseeing. I'm just not ready to develop a full time habit again...But I've been really interested in this Star Trek Online. I've looked over people's shoulders while they played it and thought: 'Oh, I could see how this would be fun..."
What about you? What MMOs are you into, and how deep into them are you?