Backups
All my data files are kept on the "D" drive, and my applications kept on the "C" drive.
I back up to my laptop in the house, manually, and to a separate external hard drive out here using a normal automatic backup program. I was using a thumb drive for my book files, too.
For knotty crap like preferences and e-mail files, I use a program called BackRex, which pulls all this information out of those horrible secret folders and lets you import it into another computer. I use this even though I've instructed my e-mail program to use a normal folder on the D drive for mail.