I might hold off on the Canon 50D. It is a brand new camera, and already there is some mixed reviews on it. Camera bodies will come and go. It's the lens that are the real investments if you are serious about photography.
It's like buying a new car. You have to figure out what your needs are (a sports car, mini van, SUV...) they all get you to the place you want to go. But you have to decide what you want to pay for it. No use getting snow tires if you live in the desert.
I am a Nikon user. But a camera is just a tool. Any DSLR is a big jump over a point and shoot camera.
Do some research.You can't go wrong with Canon or Nikon.The more knowledge you have, the better your decision will be on getting the right camera for yourself. Then go to the store and give the cameras a test drive.
http://www.dpreview.com/