How reliable is your mains power supply?

[mikeymike]

The problem is with buying kit that act as preventative measures, most of the time you don't know if they've just saved whatever you were trying to protect.

I had a power supply go bang once as a result of a power spike, I've used relatively decent (read: a little more expensive than the average price ones) surge protect 4/6-ways since then.

I had one surge protect 6-way go bang when a power surge > 30 amps blew the 6-way and a fuse in the house's fuse box, no equipment I was trying to protect was damaged though.  I think it was the result of the fuse in the fuse box being too old and not tripping immediately that caused a surge way too large for the 6-way to handle.

[mikeymike]

The problem with guarantees is that the manufacturers will try (and probably succeed) to find a loophole which means your disaster isn't covered by the guarantee.

@ KennyR

I think the basic principle applies - go for the brands you consider trustworthy, and then the more you spend, the better protection you get.  There are few (if any) systems that will guarantee that your computer won't get fried by a bolt of lightning :-)