For the last couple of weeks, it's mostly been Daggerfall and Battlefield 2, which I found used for $4.99 last Friday. Best $5 I've spent on a game in a long time. I've got a LAN party coming up the first week of March, though, so I should probably cut back on the Battlefield and get some practice in on TF2 and L4D/L4D2, all three of which I'll probably wind up playing while I'm there.
All that aside, I'm one of those people who buys way more games than he ever finishes, to the point that I have about 20 games that I've paid for but not played yet, and dozens if not hundreds that I've played but never finished. If I were to list every game that I play off and on, just remembering them all would take me a very long time.