With a 21 inch CRT, you are going to want a pretty large UPS if you want any sizable uptime during an outage. And I can't recommend the Conex, as I have one here that I am finally getting rid of. I bought it cheep at CompUSA for my server, and about 6 months later I found my server was powered off and the cable modem reset. Attempting to power on the server failed till I unplugged it and let it sit 5 minutes. Same thing kept happening, and I thought the power supply was dying. I even caught it happening once, the server would power off, the UPS would then chirp and reset, so I figured the power supply was the issue. I replaced the power supply, and had the problem resurface recently. Swapped UPSes out, and now the server has been running just fine with no interruption.

Now I need to go buy another UPS for the HDTV, as thats the one I snagged for the server now. I keep a UPS on the DLP since I have heard bad things about the bulb being damaged in power outages from overheating when the fans stop.