im not bashing the 5100, and i think a lot of people is fine and happy with a 4-5-600 dollars camera (3-5-5.1k) but if nikon put a camera model at 5-600 dollars and another one at 1000 there must be a reason (without reading all the specs)
it's like saying a Ford model is fine enough you do not need a Porsche so the Ford is better or same than the Porsche, wait, for who cannot afford and for the beginners (or pros who want a cheap second alternative) the 5100 is nice, good, perfect
but dont lie to yourself (not you :P) saying it's the same as an higher model because the Porsche will beat you every day (but hey, all you need is drive and go to work, well!)
if money is the matter than one can be happy with the bottom line of Canon or Nikon and find its 'pros' against the D3X (because if it falls or if you meet thieves you risk a lot less :D, because it's way lighter, because after all it's still a dslr, because you could invest all in FX lenses instead than having a d3sx body only.and 20 more 'because')
it's that kind of game of convincing yourself to be better looking than cinderella, just accept the range of your camera (as the d7k is way inferior to its higher rivals) and understand-accept your pros-cons.
i for example am not bothering on if the d7k is better or same of the d300s or of the even better newcoming d400, or d700 or whatever
the d7k sits in a level, and thats it.
so does the d5k and its older models.
i'd have liked a better d300s (d400?) but when it will be up it will cost MORE bodyonly, that i cannot afford, i do like a lot more the d7k than the d3100 d5k d5100 etc (or the canon entry level latest models)
nikon it's not stupid selling one body at 600$ and another at 1000+ with no differences (and we are talking about a limited time distance, not a 2-3 years difference)
if the 5100 was same or better(depending on your point of view) than the 7k, nikon would have priced the d5100 at a lot more expensive (since they are not santa claus)
cheers :P
CORRECTION: (Body Only) d5100 800$ - d7k 1500$ (d5k 650$, d3100 550$, Canon t3i 800$, Nikon d300s 1300$, d700 3.300$)