According to nikonrumors.com, the Nikon D600 has a 99% chance to be announced at Photokina.
We know it'll be full frame 24 MP, with all the now standard innovation of the past year etc. Nothing new here.
What's hot however is that it is said to be very small and light, and mostly priced around 1500$.
So, friends are going to hate me, but I believe the serious amateur has no reason whatsoever to ever spend his money on a Nikon D800 / D4 or Canon 5D / 1D if that is confirmed. I can also hardly see how Canon would not be hammered by such a camera, which means they are likely to launch a competitive product.
This is all good for us, consumers, who suffered from the upper positioning of full frame sensors - for marketing reasons essentially in the past few years- while every 35mm film camera was and still are full frame.
Now you people at Nikon can start working at affordable medium format digital SLRs :)
So save on the body and spend on the lenses !