APC is usually the tops in brand name. Depending on the model it can tell just about any OS to shutdown if power is running out. Biggest cost is the name for APC. Some others can do the same. There are some utilites out there that can communicate to the serial port of UPSes.
Distribution: RHEL 5.1 with Pieces of this and that.
Kernel 126.96.36.199, KDE 3.5.8 and KDE 4.0 beta, Plus Development src.rpm, ATI fglrx64_7_1_0-8.433-1 rpm with 3D and DRI working.
Acer 5100-5840 with webcam, ati, sdcard reader, sound, atheros based wireless, all working. Only thing not working is the memory stick reader.