I buy games about as regularly as I always did (that is, not particularly often, maybe 5-10 a year), but I've still got a massive backlog of stuff I've hardly played. The reason is pretty obvious: hundreds of hours thrown into certain games - Fallout 3, Fallout: New Vegas, Oblivion, various plastic guitar games - it gets to the point where other things don't really get a look-in. Particularly when it's stuff that requires a serious commitment in terms of time and attention span, as shown by the four big JRPGs that I've started (and, in the case of FF13, got to at least half way) and abandoned due to the sheer scale of the things. Admittedly I expect Blue Dragon and Infinite Undiscovery to remain abandoned - the former because it's too cartoony for my liking, the latter simply because I found it really tedious - but I'd love to find a gap in my schedule and sit down for a week to get Lost Odyssey done because... well, it's brilliant.
Of course, there's also the things that turn out to be awful or beyond my capabilities: Resident Evil 5 killed me in (literally) less than five minutes and I haven't picked it up since, I'm completely stuck on Prototype, the controls on Deadly Premonition made me want to eat the controller, Halo 3 and CoD4 have predictably shown my utter incompetence at the whole FPS genre... the list goes on.