nitewulf said:
lenses are the most important part. all the cameras have similar functions...mainly you'll be adjusting shutter speeds and aperture sizes. the differences of the bodies come in focusing speeds, focusing accuracy, build quality, image processing and intelligence.
i'd say get the cheapest affordable body but the best lenses within the price range.
this used to be a reliable adage in the film days, but it's no longer strictly true. cameras these days differ heavily by sensor. film shooters used to obsess over film, and not the bodies so much since they were just light tight boxes. now, unfortunately, your body specs your film as well.
however, the good news is that for a given sensor, image quality is more or less the same across all models using that sensor. even better, the lower end models using that sensor are almost always the last released, and hence have the most refined implementation of the sensor (the japanese signals guys are insanely good at what they do). this means that as long as you're careful you can still ignore the whiz bang AF systems and magnesium castings of the higher end bodies if you won't need them. basically, pick your sensor based on your photographic goals, figure out how many bells and whistles you need (re: AF, weather sealing, VF size, etc.) and then buy the cheapest body with your sensor and whistles.
unfortunately with nikon right now this means that if you want the oh-so-sweet 12MP CMOS, your best choice is still only the d90 (although there are soft rumors that a smaller body will be out next week).
imo the biggest issue is actually defining "best" for lenses. is, eg the nikon 17-55/2.8 a better lens than the 18-55/3.5-5.6 vr? there are some specific metrisc for which it clearly is: lower-light without a tripod, DOF control, distortion, goes slightly wider, much more durable. by other important metrics it falls somewhat flat though: eg, it's 3-4 times the size and weight and 10x the cost. however, we were just obsessing over image quality; by that metric it's completely unclear. at f8-f11 (close down smaller than that and diffraction will actually kill you on small sensor slrs), you would be hard pressed to distinguish between the two (it helps that the 18-55 has astonishingly good performance), and the vr on the 18-55 may actually get you a sharper shot if you're handheld with both in good light.
i'm not sure if i have a clear thesis here. the whole deal requires a fair amount of thought though about how/when/etc. you're going to use the tools you get, and optimization can proceed from there.