I was on about my 10th wireless mouse from Apple. It was a very bad design with that roller ball on top. But I recently bought the new wireless magic mouse from Apple and so far am VERY happy with it. Besides the cool shape there is no way to get dirt inside. Still eats batteries of course. Anyways, I highly recommend the new magic mouse for anyone using the mighty mouse.
Also, the new version of the wireless keyboard (alum) has a slight change from the original...only needs 2 batteries instead of 3. And so far it seems to be lasting longer on 2 then it did on 3 so I think they made some changes in power consumption.