Oh God, yes...
I have roughly 250 games in my Steam library, around 70 of those are unplayed. A lot of those are games I've received, unwantingly, in bundles. I will play them at some point though.
I have about 25 PS3 games I haven't even started yet, 10 or so still in the wrapper.
Not to mention a slowly growing backlog on GOG and a few 'classics' that I never got to play on PS1/PS2.
I've noticed that my attitude towards gaming has changed a fair amount because of it. I used to be a 'completionist' and would get Platinum trophies for all my PS3 games, and all Steam achievements. Nowadays I just play to beat the game, enjoy it and move on to the next. Though in reflection I think that's probably a better thing.
Though due to the high influx of 'games that I want to play - but not high on my priority' that I get with bundles, just because they're cheap, I've noticed my Steam wishlist is getting pretty big now too. Too much neglect towards the games that I actually want!
Recently signed up to Backloggery.com though and it's a godsend. Hopefully I can whittle away some of these numbers without ruining the experience of the games.