I have 2 different wireless keyboards.
1. Intel 900Mhz USB keyboard/mouse. Great distance, poor battery life. Seem to need to replace the battery in the mouse every two weeks.
2. Logitech wireless desktop. Includes the keyboard and mouse. Not great distance, but battery life is excellent. I replace my battery twice a year at the most.
Btw: The system with the wireless keyboard and mouse is connected to a system with a video out. This video out if wired to a video modulator. It turns a channel (125 in my case) into a computer channel. I can take the wireless keyboard and mouse to any TV in the house, tune the right channel, and listen to music (Mp3's), play a game (including mame), and surf the web.
Admittedly the picture is not outstanding since the video modulator uses a RCA video input, but with a bit of fine tuning, it is acceptable, especially for quake type games.