Backups are important... I can't say it enough. For us Apple users, Time Machine is surprisingly effective. But what makes it really useful is the hidden ability to backup over to a network share. This is something that should be enabled by default... but then who would buy an Apple Time Capsule *gasp*

Open a terminal and run:

defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1

Then you can use a Samba or AppleShare (even Netatalk) server share as a time machine backup location. This works perfectly, as Time Machine creates a disk image with an HFS+ filesystem on which to perform backups, and mounts that.