throwing in my 2pence.
i take a lot of pictures and have and still make a few bob shifting them.
the first thing to bear in mind is its never the camera that makes a good photographer , the camera can only dictate the quality of image that you can take. I have the full range of equipemnt and my most profitable images are taken with a £20 camera off ebay.
that said there are two parts to dslr camera's the body and the lens. a great body with a shit lens and your wasting your money. Most dslr will come with a kit lens, most likely not the greatest but enough to get you going.
this website here is amazing. it has virtually every decent digital camera available, and you check off the ones you are looking at and can do a side by side compare.
http://www.dpreview.com/products/compare/cameras
sites like flickr are awsome communities where you can learn alot about pohotography.
the camera section will tell you the most popular camera's in use by brand and overall (funnily enough its the iphone)
http://www.flickr.com/cameras/
Camera users are very cliquey, like Mac against PC types.. ( i'm a mac you pc scum.... ) anyway.... Nearly everybody will tell you that Nikon or Canon are the way to go, but be careful there are adequate alternative makes available , remember the body will do the processing so a c-mos chip type or a(something) is what you need to look for. compatbility of lens with body etc...
i use a sony alpha and it rocks.
Do your research before you ever go near a jessops or any such place as they have directed selling, ie certain models in stock to shift, some models will no longer be supported etc....
best of luck and enjoy snapping away