What do people think is the best full frame portrait lens, for use on the Nikon D700? I have the 85mm f1.4 and the 105mm f2.8 VR.
As always, it depends on what you're trying to do. The 85 f:1.4 is probably the best all-around portrait lens; it provides a nice working distance, mildly flattering perspective, and beautiful soft defocused backgrounds. I really like the way sharpness 'rolls off' at the edges of the frame when you focus on the eyes with such a lens at about f:2 or so.
Probably my all time favorite portrait lens was the Pentax 85 f:1.4, which was beautifully built, compact, crazy sharp with beautiful bokeh. Too bad I sold it when I went digital. Currently I use a Canon Eos-1Ds III, and I have three lenses I routinely use for portraits. The Canon 85 f:1.8 is plenty sharp when stopped down to f:2.4 or so, and it's way, way lighter & cheaper than the f:1.2 version. The 135 f:2 is actually my favorite, as I've gotten used to the longer working distance and its intense sharpness; it's great for extracting the subject out of a busy environment, like a crowded restaurant. Finally I have Sigma's 50 f:1.4, which is great for environmental portraits where I want to show a bit of background or surroundings with the subject. Very sharp, very little vignetting, and nice bokeh again.
Among your above choices, I'd like the 85 f:1.4; the f:2.8 isn't quite fast enough for indoor light, and I like the option of more defocused background.