For a basic 35mm-style setup, a solid, good-resolution camera body is the first step. A lot of the choice here will depend on how the camera feels in the hand along with features. For digital, the camera body should use a standard memory card (compact flash or secure digital cards are most common), have a high megapixel resolution, and a big, sensitive digital sensor. The monitoring screen on the back also should be big and bright, and have some form of protection from scratches. The camera body choice will determine the lens, flash and other accessory choice because each brand has different lens mounts and syncs better with items made specifically for it, whether by the manufacturer or a third-party company.
While it is possible to become a photographer with only one camera body, having two or more makes more sense. This is because more than one can help the photographer save time without switching lenses, and a second body is a backup in the field in case something goes wrong with the first.