For the Dyson fanboys, here's an interesting read.
Get a Riccar from Cleary vacuum. Excellent service after the sale. We are on year 6 for it and it works great. Takes a bag though.
Cleary Vacuum And Janitorial | Vacuum and Floor Care
I bought a Shark Lift Away Pro a year ago and think it's great. Bought it from Bed Bath and Beyond using their 20% off coupon. All the little attachments for it make cleaning up cat hair off furniture and cleaning my laminate flooring pretty easy.
I love my Dyson. I've had it for years with absolutely no problems. It managed to keep up with two cats (one of which sheds just for spite) and a Golden Retriever. Plus a husband who WON'T take his shoes off when he comes into the house.