Oh dear, I'm a junior. Is this post automatically invalidated?
I consider myself casual-core. I play a what I'd consider a decent amount of games. Last year I'd estimate I finished between fifteen and twenty. So far this year, there's been one: Mass Effect. Put 30 hours into it since Christmas. That's a little more than usual for me; I usually do about 15-20 hours of gaming a month, but that time can be sporadic. I remember putting 45 hours into Twilight Princess the first five days I had it. Usually I play far less than that, but when I have free time I'll go wild.
But then, gaming isn't really a passion for me. It's really just a past time, a hobby. A thing to do, to unwind, relax. It's a bit of fun. I try to keep up with the changing landscape of gaming and put time into the important ones (ex: Ocarina of Time, Bioshock), but I tend more toward those games that don't require a ridiculous investment of time to beat. That's one of the reasons I've played very few RPGs the past few years. They're simply too long, and I lose interest. Same with multiplayer games. I'll go for a few rounds, sure, but I never get competitive. Can't really stand playing with those who are.
The exception to this is Left 4 Dead. Can't get enough of that game.