I like my logitech mx1000, but the logitech software is just awful. it's also a little picky about the type of mousepad you use (the desk works fine but i prefer a smoother feel...regular cloth types make the pointer jump around, but the plastic coated type are perfect). You can't use apple's software because it has 5 extra buttons, and logitech's junkware hasn't worked for me on leopard at all so i just bought steermouse. i finally have all 5 buttons set up as i like them, but in firefox 3b my plugin to allow a button to be 'open link in new tab' doesn't work...
still, i get a wireless experience, good weight, battery that lasts for weeks and weeks, normal right and left clicks, normal & side scroll, double click, expose, spaces, open link in new tab (middle button), and i still have another free button waiting for some new feature.
I do like the feel of the MM, and the scroll ball is better than any wheel, but i activate expose at least twice an hour when using my girlfriend's computer, and having double click, expose and spaces buttons really speeds things up and keeps me from constantly searching around the keyboard for F keys.
I also have a microsoft wireless notebook mouse for the macbook, a bit small for my hand but it sure beats a trackpad.