Here, I have a backup box (mobo, CPU, PSU, etc..). Any of the components of the Mythtv system can be swapped for those of the backup box.

Including just moving the hard drives and tuner cards from the Mythtv system directly into the backup box.

Linux/Mythtv automatically reconfigure themselves for changes like that without user intervention, driver reinstalls, or telephone calls to Microsoft, so it's an easy swap.

A buddy of mine here recently turfed his pirated SageTV setup in favour of Mythtv, despite me suggesting he was probably better off with SageTV. But he begs to differ on that point, and is really happy he made the switch. But of course, he's a non-technical user, so he doesn't know about that kind of thing.

It was especially fun to watch his expression when he later moved the hard drive and tuner card from the original old-P4 system into a faster AMD64 box, and didn't have to tweak anything for it to boot up and work perfectly. Useful feature, that.

Cheers