Can't really be bothered listing all the games I have and haven't completed, but one thing I will do is comment on the subject.
Basically I found that when I went to uni in 1998 I gained access to the internet, and multiplayer gaming, which meant that I spent much less time playing single player games. However, a couple of years ago I figured that I was spending so much time on PC, but not actually spending much time playing games.... you know, spending too much time chatting on IRC, or spectating games. I used to have a very short attention span, trying games briefly, and if they didn't grab me within 30mins or so I'd just give up. So I made a conscious decision to start being much more aggressive about attacking games and forcing myself to play through them. Games like FPS are fairly pick-up'n'play, so I've always played those quite a lot, but titles like KOTOR, to be honest a few years ago I wouldn't have had enough commitment to play through them.
I've completed ~44 games in the last 2 and a bit years, compared to about 6 in the previous 5 years. So in some ways I'm actually bucking the trend, by moving away from multiplayer gaming and getting more involved in single player. 90% of my gaming time used to be spent on multiplayer (quakeworld), whereas now it's more like 20%.