Check out this badboy - 9 buttons if you include the left and right click and the scroll ball. It has an application switch button which I think is pretty cool. No more alt-tabbing like the rest of you stone age savages. :P
Came with two rechargeable batteries, which is what the cradle is for, besides being the cordless receiver. Beautifully ergonomic design, I must say, and has the afore-mentioned advantage of being cordless. Cool, huh?