Update: I've got my D600 and lenses! I ended up with the following:
16-35/4VR - Great edge to edge sharpness. Better image quality than the 17-40. Dang this thing is front heavy though - compounded by the grip problem (see below) it could be a bit of a pain to use.
24-120/4VR - Also great sharpness across the frame and very speedy focus. I was initially on the fence about this one, but it surpassed my expectations. This appears to be THE walkaround lens for Nikon FX. If only Nikon could produce this at the same weight with f/2.8. :)
50mm/1.8G - great value, how could I not buy it? The guy at the store recommended it over the 1.4G as have many reviewers online. I didn't try the 1.4 but quality and price of the 1.8 were right for me. Also, focus speed is slower than the zooms above and takes a little patience, so I don't think I could deal with a slower focusing lens. I also love the light weight -- it balances perfectly with the D600 body. Makes me want more primes.
I went in thinking I'd get the 105 micro but after testing it, I determined that it's truly an amazing, sharp macro lens but nothing more than that. AF-C was too slow for action portraits and images were noticeably softer for more distant subjects. It IS a macro lens after all, so I wasn't totally surprised, but I was hoping for more. I may add the macro to my kit later. I will very much miss my Canon 135/2 so I may go try out Nikon's 135/2 when it's in stock. I wish Nikon's version was a little more up to date, but maybe it doesn't matter?
My initial impressions of the new Nikon setup are overall very good. Performance and image quality are great -- these are the reasons I switched from Canon. I love the natural, film-like look of the Nikon images, even at high ISOs. AF-C is reliable outdoors, as is AF-S in low light. I like the compact form factor and the very handy popup flash (Canon really goofed by not including one on the 6D). I also appreciate small things like the LCD screen cover. Expectations met!
I was curious to evaluate the reported green cast of the LCD. I compared a picture of a white wall on the camera vs my calibrated NEC display. There may be a very, very slight greenish yellow cast but it is really very minor and is a non-issue. I also noticed that colours on the LCD appear more saturated than they really are when the LCD is set for maximum brightness (the default). Changing the setting to 'Auto' seems to be a good remedy.
The pain points for me revolve mostly around ergonomics and are mostly a result of my being used to the arguably more intuitive Canon interface. Except ONE thing - the red swoosh under the shutter button protrudes at such an angle and sharpness that it digs into the side of my middle finger in a truly painful way. It's even worse with a heavy lens. I didn't notice this in the store but after 10-15 minutes of post-purchase shooting I really felt the pain. I have no idea how this design problem made it to production - rather worrisome really! Do other Nikon cameras (such as the D800) have the same grip shape? Maybe I'll build up a callus there and it won't be an issue...
ps. Is it possible to post images into the forum?