I learned a long long time ago to always back up my data--I still have disks from my last PC, which I got rid of in 2003, though I have no idea why I still carry them around. Habit, I assume. I'm so conscious of it that I upgraded my Powerbook's operating system when Time Machine became available, simply because it made backing up data so much easier.
Which is why I didn't freak when I woke up Saturday morning and my Powerbook was nonresponsive. Gray screen of death. Blinking file folder with a question mark on it. Happy 41st birthday to me indeed. It's in the shop now being outfitted with a new hard drive in large part because I can't afford a new computer right now, but I'm pleased that my data is safe on my Time Machine.
Or rather, I assume it is, since I've never done a system restore using it. I'm hopeful and confident, but I won't be completely sure until I actually have it up on the screen.
But since I'm paranoid, I also keep a lot of stuff in the cloud. My poems and reviews are almost exclusively on Google Docs now, and my gradebooks as well, which is important, because even if the data on my Time Machine is safe, it's not accessible right now, and the end of the semester approacheth at a fast pace. Put simply, I'd be boned if I weren't in the cloud right now, because at least some of my students have tossed quizzes they've gotten back, not to mention essays and midterms. I'd have to reconstruct an entire semester worth of grades, which would add a triple load of suck onto an already tiring semester. I had to do that once--about 4 years ago when I dropped my laptop, the one I'm typing on now while my newer one is in the shop. Cloud computing is awesome.