I back up my files like crazy. I think it's very important and my past experiences have taught me something valuable: the PC may go anytime. Without warning.
There are many places where I back up my most important files (final drafts, WIPs, personal data files, financial information, contact information, etc.):
- three hard drives on different machines
- SD disks (so I can take them with me)
- Apple iDisk (250MB)
- An online account (30MB storage)
- MSN storage...
My contact information is on my PDA, all my PCs, as well as two online acounts.
In this age of cheap PC and viruses, it's very important to have redundancy. Save yourself a lot of grief.