A couple of days ago I spent 1600 points on the final two Fallout 3 expansions that I was missing... though I doubt that helps you.
Generally I'd just spend all my points on DLC for Rock Band but I'm not playing plastic guitars as much as I used to so I've stopped buying points altogether. The 2100 points card I bought this week was the first since June. Two expansions for Fallout 3, two songs for Rock Band, a song for Beatles Rock Band and there it was gone, 20 points left. I need 250 points for the final Skate 2 expansion but since the minimum we can buy in one go is 2100, I'll have to wait until there's a lot more stuff I want otherwise it'll just get wasted on Rock Band.