I have an oversized steam collection myself. I tried sorting my games into categories last night so I could see at a glance games that I was currently playing vs games that I had already played through vs games that I had yet to play. I found out that I have something like 20+ games that I'm currently 'playing' to some extent. I really need to organize this a bit better. Especially since I tend to start a game, and then at the first sign of boredom or frustration, I fall back to something else (usually AI War). And I've only got a few short months until the summer sale buries me in another 50 games...
I had to do that a while ago just to keep track of everything. I have one for stuff I'm currently playing (or at least pretending I am, even if it's only once every couple months), one for multiplayer stuff that I mostly or only play with other people, one for things I'm not actively playing but keep around because they're good ways to kill a few minutes here and there (e.g. Audiosurf), one for stuff I haven't started playing yet, and one for stuff that I want to keep hidden (either because it's terrible or because I'm finished with it and know I'll never want to play it again). The stuff that's not in any category gets to hang out loose at the bottom of the list, because I've already played it, am not playing it anymore, but may want to go back to it at some point or show to someone else.
It's good for keeping track of how much stuff I'm already in the middle of, along with helping me avoid playing more than one thing in the same genre at the same time (playing two huge RPGs at once never ends well, but I can still have a dozen games going at once with the wide range of interests I have), and I can also easily see how big my backlog of stuff I haven't even started yet is, which is good for encouraging me to buy less stuff when that category is larger than usual, unless it's really, really, ridiculously marked down.
