In this era of POCO deregulation, running a computer without a UPS is an open invitation to disaster. I've put one on my computer, my entertainment system, and, with all the short power bumps I've been seeing lately, I'm going to put a little one on the electric clocks in the bedroom so we can reasonably expect the alarms to go off about the right time.
I am suprised by the number of people who remember to protect the $1000 computer and completely overlook the $3000 plus home entertainment setup.