I'm always a bit surprised nowadays when I read on a message board or mailing list that some writer or editor has lost two weeks, two months, or two years (don't ask me why, but it's always "two" something) of work because of a hard drive failure. I thought that losing more than a day's work was something that went out with floppy disks. So, just a friendly reminder--back up your files (preferably every day).
I use an 8 GB flash drive, and just copy my e-mail folder and any files I've worked on that day. I also use my older 4 GB flash drive on occasion to make a second copy of the e-mail and anything important I'm working on, such as a book manuscript. Finally, I store an off-site backup with hubby, although that's probably not as up-to-date as it should be.
Yes, I'm a bit like Mr. Monk on this (and many other topics), but, remember, "it's a jungle out there." :-)