SPEND AS MUCH AS YOU NEED ON A GOOD UPS!!!!
I can't tell you how many times I've had or seen a UPS save projects, hours upon hours of work, and once, even a theatrical production. (The lighting board was plugged into a UPS)
The best kind to get are the ones that will communicate with your computer and shut it down if needed through USB.
P.S. I have an APC Back-Ups RS 1300
, and the LCD is really useful. I have my Mac Pro, 30" ACD, Cable Modem and Router, Vonage, cordless phone and speakers plugged into it. Everything is running at full, I have Photoshop, PTGui, iTunes, and some other stuff open, Music Playing, and I just unplugged it. I got a message on my computer that said "Warning, your computer is now running on UPS Backup" and I looked down and it would have kept running like that for almost 15 minutes. I have it set to shut my computer down when there is only 3 minutes left on the battery. BELIEVE ME, its worth it!