Buy a D600 or a D700 ?

If it would be an usual reiteration/changing generations I would say go to the new one. But with all these quality control issues and the way Nikon handle them (no official acknowledgement from Nikon at this  time), I'd say to wait. Do not encourage Nikon to treat their customers like a 3rd world or something. Nikon seems to be comfortable with this approach. Do not give Nikon the chance to transform itself into a Canon-kind-of-quality-is-good-enough-to-get-your-money company. Nikon D700 is an incredible sturdy, totally predictible camera to use. I will say this again: D700 is a reliable camera. It's easy to know it and easy to use. It's a dream! Of course, D800 and D600 were released with the clear intention to be more than that, but, unfortunately, they're not. Wait for all the problem to be solved. Give your money to Nikon only when they are honest enough to provide you with a product that's meeting their claims.