Partially echoing what was already said: - Stick to APC - Avoid the low end "workstation" models like the plain BackUPS. As a minimum get a BackUPS-Pro. SmartUPS are better. - Use the sizing app on the APC web site - Careful of your mains power. Besides what was mentioned for generators, accidentally chaining an APC UPS into AC provided by a server room UPS can kill the downstream UPS. - For controlled shutdowns on battery exhaustion, check out apcupsd. - Decide whether your UPS will power one server or a few. If you're powering a few, decide whether the control is master-slave (which you can do with a serial/USB cable to the master, then network to the slaves), or if you need the more expensive setup where the UPS talks directly to multiple servers. I think the former is fine (as long as your network switches are on the UPS), but ymmv. Devin