I gave the microsoft line of wireless keyboard/mouse combo a shot a few weeks back and I just wanted to say that I ended up returning it. It states that you should keep the receiver "8 inches away" from any sources of interference. I moved the receiver all over the desk in varying distances and I just couldn't seem to get a steady, reliable signal. This meant that it would cut out when I was typing so I would lose keystrokes when coding and during gaming sometimes the mouse not moving would get my head blown off in Unreal Tournament.
Maybe I had a bad unit, it seems other people like these tools but I found them to be fairly unreliable. I'll stick to my corded world and dealing with my son babbling in babyish and reaching up to yank them.