I've never been a fan of wireless input devices. Since basically every radio frequency device in one's home uses the same frequencies, it's pretty much guaranteed that your wireless land line phones, your RC cars, and your WiFi devices, etc. will cause interference, which will screw with your mice and keyboards. Also, the wireless mice my work has made me use (they don't like buying new mice, so pretty much every mouse they have is either wireless, or broken, often both) eat batteries for breakfast.
So, I can't say I've had many positive experiences with wireless input devices. Yay cords!
As for security, I think this entire post is a moot point. To be close enough for a wireless mouse or keyboard to be compromised, one would need to be close enough to the machine to just sit down in front of the thing. In other words, they need to be so close, they could simply start typing or clicking like they normally would.