I have a 1TB internal HDD and a 300GB external HDD. I have the internal HDD split into two different partitions, one for OS and critical programs and another just for games, so that should I ever need to wipe my OS and reinstall, I won't lose the data on the other partition (I hope). I have the external HDD for backing up very important files, whether it be music, documents, or video, though I have to be very picky because 300GB doesn't get you far these days. I run with this setup because it's all I can afford, as I'd love to have more storage space.