My backup for a multi-boot laptop that other solutions (e.g.: running from one OS) don't seem to work for:
1) Buy a second copy of your main hard-drive + USB Interface (SATA enclosure)
2) Boot Linux on computer using CD
3) Use dd to mirror entire HD to external HD. Run before you go to bed, setup to shutdown when done. Save stdout/stderr somewhere like a USB flash drive.
4) Wakeup to a backup.
The advantage of this is when your hard drive fails, recovery is about 60 seconds away. Swap out one hard drive and you are done. Or you can recover specific files by just using the backup HD like a normal external HD, since everything is just under normal filesystems. If you'll be on business for a while take your second hard-drive with you (try to store somewhere it won't get stolen with laptop).
I actually keep two mirrors, partially because of travel and wanting to have one backup with me. This also makes sure that if your computer fails half-way through doing the mirror due to a power surge it doesn't fry your original + mirror. Keep one at a friends house or similar.