Just make sure that the UPS has a reliable surge protector with attached equipment warranty, and can supply enough power for everything you plan to plug into it.
The APC models have a nice feature called PowerChute, which will safely shut down your computer automatically if the remaining charge on the UPS gets too low.
As a rule of thumb, make sure the total wattage of the UPS is higher than your PSU watt rating, and add on the draw of your monitor (Amps*120V=Watts with household current). Most UPSs will have plugins for just the surge protection and not power, so you could plug non-critical peripherals such as speakers, router, modem, etc. into that and not need to power them.