Hi, Nikon is a very good camera, and you can get very good used lens at very reasonable price.
If you like to have one of the best lens out there for peanuts look for the Nikkor 50 mm 1.8 or the 1.4. The 1.8 cost less than $ 200 and the quality is equivalent to a $ 1000 + lens. the 1.4 about $360. Excellent lens for low light.

When you upgrade go for a Nikon D200 is awesome, I know I have one. Body only $ 1.700 a bargain
Cheer