Several things I like about this. It's a good play from their TV campaign that is ubiquitous. This makes you want to play with sound. It is very engaging from a web standpoint because it essentially interacts with the web page itself. It's not too long. It's funny. All around great use of video for a web ad. It also reinforces an argument Mac has been trying to make for some time: you don't get locked into a mac silo by switching — you can operate with Windoze just like anyone else.
Takes up a ton of space, but I'm betting it was worth a pretty penny.