Save them up to buy a PC.
lolololol
But seriously, maybe some DLC for another game or something? I hate their ridiculous MS points system - if the PSN store (which is terribly organised) and XBL (which has the stupid payment system) were smacked together in some form of cocaine-induced orgy, the consoles would have stores I'd actually want to go into for a general browse instead of just when I need to get something off of there.
Anyway, back to my point, most DLC is around 800 points I think, so buy that, and feel free to feel mildly cheated when you finish it half an hour later.