The Dyson DC17 Animal
This is THE vacuum cleaner. Friends have had them for years (cardigirl and corgwyn to name at least two) and really like them. I've used one on occasion and can only say that it really kicks butt.
A while back I was watching one of those odd little pieces on Sunday Morning, where the reporter was covering the big vacuum cleaner races. The contest was to see who could get up the most dirt from a fixed area of carpet in a fixed time. They measured it not by how much was in your bag or container, but by how much dirt a special vacuum could get up after you were done. That vacuum as the Dyson.
This picture doesn't really do it justice as the top is a very deep metallic royal purple.
(Edit: fixed picture link)