"THE" camera to get is the new Ditgital rebel with a 50 or 100mm macro. I have to shoot products all of the time and am getting this camera under the recommendation of many fasion and product photographers I know. They all heavlily lean toward Canon and they all use a D1s.
The more hardcore product photographers use a meduim or large format with a digital back.
YOU CAN NOT GO WRONG WITH THE DIGITAL REBEL!! Buy the body and get some good glass. skip the oem lens.
The nikon D50 is nice too. Unless you make your $$$ as a shooter, no need to spend any more $$$.
All in all, you can get great photos from a not so pricy camera. The most important thing for product photograpy is good lighting and the best tripod you can afford.