Picked up a few achievements in Geometry Wars 2 Retro Evolved... Some of the rest look insanely hard. Good game.
I've found myself going back to Need for Speed: Hot Pursuit. I'd lost my save in The Great Hard Disk Format Fudge Up of July, so I didn't think I'd go back to it, as it would be such a slog to get back to a level from which I could get the rest of the achievements... However, playing it now, it turns out that it's just too much fun to not go through it again.