I don't normally talk about computer equipment here, but I recently purchased the K750 wireless keyboard by Logitech. It's amazing because it is solar powered and therefore requires no batteries. Their manual says it can remain powered for 3 months in total darkness. I believe they tested this in my office. Also of note, I bought the mac version of the keyboard. However, it also works with my PC, though I had to fool with their software a bit for the function keys to work.

The K750 is also a good deal cheaper than the official Apple wireless keyboard.

Previously I had an older version of the Razer Deathstalker. It was nice, but there were wires everywhere. The K750 is nice and clean, and I haven't noticed any perceptible input lag / delay.