CCC is the way to go for one-shot, sure-fire clones. Add PSYNCH (the instructions are with it), and you can do a differential, bootable clone in a relatively short period of time.
Another free (not even donationware) option is the crusty-looking but effective LaCie Silverkeeper (have a look at VersionTracker to find it). It's not quite as powerful as CCC, but it'll do a differential, bootable clone from one drive to another, and you can select specific files not to replace, or not to copy.
Silverkeeper's one big advantage for automated, scheduled backups is that it includes the ability to have your Mac wake at a specified time to do a backup, and to execute a backup when you first turn it on if it was powered down at that time.
My Mac wakes from sleep at 12:05 every night and does a complete clone of the boot partition to a partition on a 2nd internal drive, for example, and it's run smoothly since the release of Tiger. If you do something like this, you want to be sure to tell spotlight NOT to index the backup partition, and Silverkeeper not to replace the invisible Spotlight folder on the target drive or it'll end up indexing the whole bloody thing every day.
