Leopard’s Time Machine feature is spurring a lot of discussions on backups, and that’s a good thing. A lot of the discussion, though seems to be centering around backing up your whole machine, and whether or not your Time Machine drive is bootable if your Mac goes down for the count. (It’s not.)
I may be in the minority here, but I don’t backup my whole machine — I don’t wind up with a mirror image of my drive that I can swap into my Mac and reboot as if nothing ever happened. That would be an ideal situation, I suppose, but I’m more concerned with preventing data loss — things like pictures, family movies, important documents, receipts, email, songs I’ve purchased or ripped from CD, etc.
I have my original installer discs for both my Mac and my applications. If my computer crashes, I can just re-install them. It’s the irreplaceable stuff I want to make sure I protect. My backup strategy is to have multiple backups of my home folder and the separate hard drive that houses most of my media. Backing up those items takes less space and less time — and that makes it more likely that I’ll do it.
The fact that Time Machine doesn’t create bootable backups doesn’t matter to me in the least.