When I first heard about Time Machine, I thought it sounded like a cool feature but something I'd rarely use as I can't really think of a time I've accidentally deleted a file I actually needed. Just now I went into iPhoto to look for some pictures I took on a recent trip. I had transferred them from my MacBook to make space on the hard drive. I imported them into iPhoto on my iMac then deleted the original folder (3 GB or so). I went to look for them tonight and realized that I never in fact imported them into iPhoto. I got that sinking feeling you get when you realize you've lost something important and irreplaceable. Then I remembered Time Machine. Fired it up, went back in time a few days, and there were my pictures. I just restored them and they're all there . Seriously, Time Machine alone makes Leopard worth it.