I'm sure by now everyone knows to backup their HDD's. Externals are so cheap these days cloning your internal HDD is a non issue. If you have a failure no sweat it's backed up.
That's irrelevant. If your internal HDD dies, how are going going to restore from your backup? You need to boot your computer to do that at least. To restore from Time Machine, you need an OS X install disk. Now that we can't have one, how are we supposed to proceed if our internal HDD fails? Buy a new HDD, yes, and then what?
I know there is a way to put the Lion installer (which includes the restore utilities such as the Time Machine restorer and Disk Utility) on a DVD or USB drive, but I think there should be a giant button somewhere that makes it easy for you.
Something like this should happen at some point:
"Do you want to create a recovery drive?" <Yes> <No>
"Please insert a DVD or USB drive and press OK"
"Done."
Maybe it could be an automatic prompt, or it could be a button in Disk Utility. It could just clone the restore partition onto the external media. Then you could boot even if your internal HDD fails, and you can transfer your files back onto a new HDD from backup while booted into recovery mode from the external media.