When Nikon said the D800 (which you can win here) wasn't meant to be the D700's direct successor, I'm not sure many trusted them. However, recent rumors show something in the works that would fit well into that realm. And so, we now have a lot of people talking about what could be a very cool camera -- with a few key things left behind...
Aside from the odd direction of naming (though Nikon did it back in the day of the D70), the D600 moves forward with a rumored 24MP Sony sensor (D3x much?). It should include HD video recording features, dual SD card slots, and time-lapse control built in, but will lack HDR functionality. There's one problem with all this: the Nikon is supposedly not including an AF motor into the body. This would leave D600 users stuck to use AF-S lenses only, similarly to the D3000 and D5000 series bodies.
While some might not find this 'bad,' I think it'll be detrimental. Sure, they'll still sell a ton of these, given the expected $1500-or-so price-point. But there are some excellent prime lenses that aren't AF-S lenses and that are sold dirt cheap. Nikon got away with doing this in the D3000 and D5000 series because a lot of their lower-end AF-S offerings have been geared more to the smaller DX sensor format. But those wouldn't cover the full-frame, FX sensor of this D600. Want a fast prime lens? You'll be stuck with Nikon's f1.4 primes, the over-$1500 24mm f1.4G, 35mm f1.4G, and 85mm f1.4G. Okay, that's not fair. They have a great 50mm f1.4G for just under $500, the 50mm f1.8G for $230, and the newly announced 28mm f1.8G for $700. But assuming you'd want both a 50mm and a 28mm, you're still stuck paying almost what a D800 costs when you add that to the cost of the body. And when you can get a great 50mm 1.8D for $100, that D800 starts to look like a pretty sweet deal again!
I think a bulk of consumers won't see this. Though over time, they might become more educated and better-advised by dealers. Time will tell, but I'm hoping this part of the rumor isn't true...what do you think?