http://www.nikonchat.com/nikkor-18-135mm/

Nikkor 18-200mm f3.5 on a D40?
Is this feasible considering the price? Or should I get a place with a D80 kit 18-135mm lens? Thanks.
I think it is better with 18-200mm AF-S VR in the D40 18-135mm on the D80. While the 18-135mm is sharper, it suffers from more distortion and aberration color. The 18-200mm lens has a longer range and fewer problems. Thus, the 18-200mm lens is the better choice. It is more expensive than the 18-135mm, but to get the D40 instead of D80, can make the difference. Therefore, the question becomes the difference megapixel D80 (10MP) compared to D40 (6 MP). In practice, it is difficult see any difference in any print size 13 "x 19" or smaller. Few people print more than 13 "x 19", and thus again, no need to spend money on the D80. So, yes, the D40 with this lens is very feasible and would be an excellent choice.
Nikon D200 10.2 Megapixel with Nikkor 18-135mm Zoom