While I do have a surge protector to protect against overvoltage (hopefully), I have nothing against undervoltage. When a lightning storm hits, I had the lights flickering at some point. The PC continued to run, but it got me thinking of getting a UPS as a way to a) have a clean 120V/60Hz power source and b) have a way to shut down the PC in case something bad happens.

I heard not all UPS' protect against power spikes, so I wonder if someone has a recommendation? It does not need to keep the PC on for a long time if the power goes out, it's good enough if it shuts down the PC after 5 minutes or so.

There are 2 PCs connected. One is a Core i7-860 with a Radeon 5870 running Windows 7 Ultimate (so quite power hungry. It uses a 600W PSU but I have no measurements of the actual usage), the other one is a Windoes Home Server, running WHS/Windows Server 2003.

Any recommendations in the low-price segment?