If you only own one PC, where does it back up to? What media?
If it backs up to its own HDD, how do you explain why a 1Gb file really eats up (at least) 2Gb of space? Does backup equal "current image" or "historical archive"? How do you define "important stuff" without taking everything? What order do you select them in, so that when the backup fails/fills up, you've got the "most important" on there, and not the rest? Encrypted of course - where is the key? Everybody's mileage varies, but I like the idea of having a USB keydrive, and a weekly prompt of "please plug the backup drive in and leave me switched on overnight".
