Microsoft's mouse
One or two posts here might be (unintentionally) misleading. The Microsoft Bluetooth mouse - and I'd imagine the Logitech one as well - works fine. Right click automatically maps to control+click, and the scroll wheel works. This is all the majority of folks will use a multi-button mouse for.
The extra fourth and fifth button, though, can only be used for Expose. You can't map them to any specialized functions.
Also, you don't need Microsoft's Bluetooth adapter. The mouse works fine with Apple's built-in Bluetooth.