Word of warning just by chance my OSX hard disk was corrupted today. Luckily I had my Snow Leopard OSX disk so that I could use the disk utility to check what the problem was and attempt a repair. I had to reformat but it has made me think that keeping the disk around would be a good idea.
I suspect that Apple would suggest that that was what Time Machine was for. But physical media is still nice. Supposedly you'll be able to buy a USB install for $69 next month.
Is anyone else experiencing these kinds of problems with TM?