Oh, and the scroll wheel is amazing, as it has a clutch which you can set to automatically release if you spin above a certain speed (you can also release and lock the clutch by clicking it).
A good flick when browsing in the AB list, releases the clutch and sets the wheel spinning at just under mach 1. The page wizzes before your eyes, and when you get to the bottom, it bounces, and starts wissing back up again. (Not terribly useful, but good fun - I think it's designed for gaming)