Ok here goes. I had one of the better ProSumer P&S Cameras according to dPreview. I had an olympus c-8080. ProSumer cameras are kind of a mix between dSLR & Point in Shoot in that they have a lot of the features of a dSLR like aperature priority, shutter priority, RAW mode, ect but they don't have changable lenses. Sometimes they have add on filters or extensions but these aren't really changing the lens. I liked my C-8080 and it took pretty good pictures but there were definitly limiations with it. It was so much slower compared to a dSLR (writing an image to the camera after you had taken the shot especially in RAW mode and the zoom was slow too). Also they start to produce quite a bit of noise at 400iso and above. The reason they produce a lot of noise is the size of the CCD. The size of the CCD on p&s is quite a bit smaller than a dSLR. Generally the more you pay for a camera the bigger the CCD is. Unless you spend a lot of money it still isn't going to be quite the size of a 35mm frame. I think canon has one of the cheapest right now and its right about $3000. The biggest things for dSLR are changeable lenses. The lens quality is so much better and you will definitly see it. There are so gotchas though. Since you have changable lenses you will eventually get dust on the CCD and you will see dust particles in your picture. You can clean this off yourself but it can be quite a pain and sometimes i think people end up sending their camera in. Also good lenses themself can cost more than the camera. Go look at a nikkor 18-200mm VR or a nikkor 70-200mm VR. They are about $900 and $1500 respecfually. So you can see it endless on what you can spend. I just bought one of the most highly rated lenses for its price. The sigma 70-300mm apo dg and it was $195 shipped and thats very cheap for a lens. Hope this helps.
ncage