I switched from Canon about 8 months ago, and while I love my d700 I'm having a hard time getting the out of camera images to look realistic. What I mean by that is the images are incredibly warm, with an almost amber cast to them. I will admit that my picture setting is usually on vivid and I've been using automatic white balance. Obviously the wrong combination. What would be better? Particularly for portraits.
First, I would say that proper white balance makes all the difference, and automatic doesn't always do the job. Neutral and Portrait are big improvements over Vivid, but I use D2X Mode 1 on my D700, which is an optional Picture Control. I think it's usually the most true-to-life setting. You can download it here: http://nikonimglib.com/opc/
I rarely use Vivid on D700, only for some landscapes when I want to emphasize the rich colors... For anything else I am always on Standard and I shoot RAW. The AWB works fine for me unless I use various kind of light sources.