I recommend APC as well, great products and excellent customer service.
Had a 5+ year old BackUPS 1000 fail and was well past the warranty, emailed support about testing the unit before getting new batteries since the original batteries swelled up inside and the UPS just beeps and shuts off with or without the batteries installed.
They asked me for the serial number and a shipping address and over-nighted me a BackUPS RS-1200. Didn't ask for proof of purchase or anything. I was very pleased.

here are pics of the old one with the swelled up batteries and the new one I received,
http://transamws6.com/pics/backups/