Which vacuum cleaner should I get?

I've had a hoover windtunnel for many years and it doesn't seem to be cleaning that well anymore. I'd like to buy a new vacuum cleaner soon, but not sure which one to get. I think that my kids and I are allergic to dust. So I want something that really gets the dust and traps it. There are no pets in the house. I also would like the vacuum cleaner to have something for cleaning hard to reach areas, such as ceiling fans. Any suggestions? I'm considering Oreck for its light weight.