...Microsoft optical mice are just about the best I've used.
I have a Wireless Intellimouse Explorer 2.0 on the Mini (the smooth tilt wheel is funky):
[image|http://i66.photobucket.com/albums/h262/pwhysall/Mice/WirelessIntelliMouseExplorerLeather.jpg||||]
and an original Intellimouse Explorer on the PC (mine is substantially less nice to look at after 3 years):
[image|http://i66.photobucket.com/albums/h262/pwhysall/Mice/IntellimouseExplorerversion1.jpg||||]
Neither has ever missed a beat.