I know many people don’t like the idea of buying a game without a box but I’ve used STEAM a few times now with great success. If you happen to wipe your box, you can always reinstall the software since it’s account based, sort of like linking your hotmail account to all your games.
Right now, STEAM is having a huge sale, like 50% off almost everything they have. How about Bioshock 1, 2, Borderlands and all the exp packs plus 20 more 2K games for 85$? Crazy.