well.. in my opinion for the difference of a prosumer and a DSLR..
prosumer cams are the so called "all-in-one" camera, can zoom very far, can record videos, can take decent pictures that allows you to print your photo up to super A3 size. you can even take a telephoto macro picture with a prosumer.. if you want extra zoom, you can get yourself the 1.4x - 3.2x type of TeleConvertors, that may cost up to $150 the most.. Or if you want the wide angle convertors, from 0.45x - 0.7x, costing you at ard $50. so overall, the setup for Prosumer cams are like a compact DSLR but limited dpi image. especially night shooting, it's really hard as prosumer cams produce lots of noise during night photography.
on the other hand, a DSLR, as agree to the others, the lens is the important thing, there are many ranges of lens available, and they do not come cheap. the body is just a secondary item that allows you to process a good quality picture no matter where you are or what time is it. Like many others, spend a good sum of investment amount into a good body, for lens, there's never-ending :bsmilie: and it's not $100 lens.. those lens could cost you minimum of $350, and the most expensive at 6 figures..
so it's up to you =]
i used to own a FZ18 before, now im at DSLR stage.