I recently researched and bought a Hoover Windtunnel. If I had more money, I would've gotten the Meile (sp?) as they get great ratings, are quieter, have longer cords, etc.
I really like the research Consumer Reports does, and the Windtunnel is one of the highest rated vacuums. The Dyson's don't perform that well in their tests, but I know a lot of people really like them. I got the Windtunnel on sale at Kohl's and got Kohl's cash back, so it was only about $120 in the end and it is an awsome vacuum - even self-propelled.
Good luck!