Second the 70-300mm AF-S G VR ED, just picked one up today.
Thing is you can heavily crop at 300mm and its sharp, try that with some of the cheaper 3rd party lenses.
Ive got a D90 and its great for my use. Would be nice to be able to meter on the manual prime lenses i have but its not a problem as you have to think about what settings your using.
D90 manual can be download off the web.
Have a look at the picture control settings, things like saturation and contrast will help to get more vibrant photos straight out the camera, though with the Nikon glass you won't need to tweak things too much
Something like Thom Hogans Complete Guide to the Nikon D90 might be worth a read but all of what Nikon freak said really.