Mr Green,
Windows 7 backup works well for me. I use the "Let me choose" option when setting it up (or changing it) as this allows you to specify any or all of your drives (or their subfolders) for backup.
The MS recommendation is to use an external drive as the backup drive, for obvious reasons.
The first backup takes ages but subsequent backups only process any changes since the last backup. This takes much less time. You can actually work on something when the backup is in progress.
I have the auto backup schedule set to once a week; but I set off a non-scheduled backup if I have done significant work that created, deleted or changed files. The weekly backup still runs automatically.
Having just acquired a new PC, I have done a lot of backing up of all sorts of bits & pieces, using the Win 7 backup file from the old PC (on an external drive). The Win 7 backup's facility for retrieving such files, then writing them to somewhere else on the new PC, has worked every time.
I have also, in the last 6 months, rebuilt a PC using the system image and data backup files from Win 7 backup facility, following a slight disaster when removing XP from a dual-boot drive. Again, no significant problems although a couple of programs had to be re-installed to get the Registry right.
It would be nice to have a real-time backup service running in the background, though. Many of the "free" programs to do this - the ones that come with HD drives, typically - seem to have all sorts of glitches; I find myself unable to trust them.
The ladywife does use a Samsung program that came with her USB3 external drive (as well as using Win 7 backup). So far no problems that weren't fixable - but it was a bugger to set up.
But in the end, I also copy over the whole TS2010 User/local folder periodically to another external drive. I also tend to make CDPs of any route/session that I've spent a lot of time messing with - just in case.
Lataxe (positively paranoid when it comes to backing up).