Hey Gregg:
I bought a D5000 for my daughter. I run 2 D300s, and a D200, and still have a D70. First, everything is the lens, once you are working with D300 technology and newer. The D300, D90, D5000, D700, and D3 (and 3x) all use processors that have better low light resolution than the earlier models. If price is important, I'd buy the D5000 and spend the rest of my money on lenses. If you read Ken Rockwell, he'd convince you to buy a D40 and good lenses. He's not neccessarily wrong.
Lenses, lenses, lenses. FAST lenses.
My f2.8 300mm VR AF is spectacular. Still, too big for many applications. My f4 600 (manual focus)is outstanding, but so heavy and big, requiring a monster tripod and gimbaled head, that it is only good for shooting out of blinds in pre-set situations. I love the 2.8 80-200 AF, etc, etc. But, even though these fast lenses give the best results (often dramatically superior) all of them are extremely expensive and heavy. I lugged the 300 on a monopod all over the Australian Northest Territories with my bow in the other hand. Loved the pictures, but it cut into the experience a bit.
You might try the 18-200 Nikon AF VR and the 70-300 AF VR as your go to lenses. They are good, small, and serviceable. They are NOT capable of giving the same kinds of images acccross the board the pro-level 2.8 lenses do, but the trade offs may be worth it for a hunting camera.
As an example, Karen and I are going to Venezuela Fly Fishing in March. I'm taking the 18-200, the 70-300, and a great Tokina 11-16mm AF. For a lot of reasons - corruption and theft, space, weight, water - I'm not risking my best lenses. But I'm going to take my D-300 Nikon body for sure. Plus a Panasonic waterproof 12 megapixel HD video pocket camera as a backup.
There's no free lunch, everything has trade-offs - Just like archery. :-) - Jay Campbell, JD