Any recommendations for a bluetooth mouse for a every week heavy traveler?

Its got to work with Mac and Windows

Its got to be normal size (not the huge desktop ones, but also not the tiny tiny ones just for travel since I will be working with it 8 hours a day)

I've got a IBM X41 with builtin bluetooth and an Apple iBook.

I don't really care if it charges via usb or has a little battery.

oh...and of course two buttons