Upload & Sell: Off
I'd be tempted personally to go with the 28-70 f2.8 for the pro build and darn good IQ, but the Tamron is honestly a better value if you can live with the more plasticky build. I think the 24-120 is also a very good suggestion, maybe not quite the IQ of the 24-70, but still better build than some others you are looking at and a fantastic useful focal range.
As for the two Nikkor 24-85's (not the new VR version)... I've owned them both and would take the Tamron 28-75 over them all day long every day. It's plain got better IQ. The AF isn't quite as fast as the AFS version Nikkor, but it's at least reliable. The f2.8-4 has no motor, and even on better pro bodies will never be confused for a 24-70 speed wise. It just feels dated to me. I sold mine immediately after getting the Tamron, while I still kept the AFS 24-85 for my daughter and a lightweight throw-around lens. It's okay, reasonable IQ, decent build and good AF performance.
The 24-70 is the cream of the crop no question, but if you can't justify the price, I'd be going Tamron if you want bang for the buck, 28-70 if you want pro build and very good IQ at a slightly higher cost, 24-120 if you want versatility above all else, and the new 24-85VR would sure intrigue me if I were a new D600 buyer... maybe wait for reviews on that one.