What is a professional nikon camera?
I'm looking for a nikon camera but, but has a good price. I'm willing to spend up to $1, 500.
You aren't going to buy a professional grade camera under $1500. You can, however get the D7000 and a LOT of the pros are using them as a secondary or backup camera these days. They are a pretty impressive camera. It's positioned in the semi-pro arena and has some awesome features. It will serve well for amateur, avid hobbyist right through lighter professional work very well.
It's a well rounded camera with a good mix of the cameras used for other things.
A "Professional" Nikon DSLR will not cost $1500 try about $7000.So obviously you do not need a professional DSLR. For your price range you could buy the new Nikon d7000 which is a great DSLR for the money all the features you will ever need, highly recommended.
Technically, any Nikon camera you use to sell a picture but if you are after classification, then start at the most expensive and work your way two, three or four models down.
You could pick up a D90 for less than a D7000. With the extra cash you could spend it on other accessories like an extra lens or a tripod head or speed-light flash.
Unless you are going full-frame (ie. D700 and above) it's not going to get you professional quality photos.
Is that your short term or your long term budget? To get the most out of your money, spend no more than about 40% of your long term budget on the camera body - save the rest for good lenses, tripod and so on. These are more important than the camera body, You'd have to spend at least $2500 to get a significant improvement in image quality from the camera body over the entry level ones, as these usually use the same sensors as the "prosumer" grade cameras costing $1700 or so.
But don't buy additional gear right at the start, just save the rest of the money for a while… Use a kit lens to find out what you really need and then buy that after half a year or so with the saved money.
Look at the D3100, D5100 (if you care about video too) or a D90 (if you only want to take photos). Buy whichever you prefer with a 18-105mm kit lens and just have fun with it.
Nikon D3100
Nikon D5100
Nikon D7000
All are excellent and have great image quality, it depends on what you want. D3100 for best bang for your buck, D5100 for articulating screen and slightly less noise and D7000 if you want to do pro sports on a budget.
Here's a DSLR Buying Guide - http://www.the-dslr-photographer.com/2009/11/which-dslr-to-buy/
The first thing that impressed me was the D7000's ability to focus in near darkness. I was astonished by this and wasn't expecting it. But the most impressive aspect of the camera is its dynamic range. Shots that would have been blown out on the D300 are not so on the D7000. This feature is reminiscent of film cameras. The other major benefit is the D7000's truer color rendering.