A guy at slashdot has summed up the problems with wireless keyboards and mice:
Your decision to move to a system that requires an independent power supply (batteries) is an invitation to Murphy to send his law to your house / place of work at the most inopportune moment.
Oh, and radiation. I’m sure it’ll kill you too. Bluetooth will force you to visit your dentist too.
Plus what are you going to fight off the ninjas with if you don’t have a mouse cord?
Holy surrealism, bantha!