I'm looking at picking up a zoom lens from Nikon and looking the the new 70-200 AF-S FL ED VR and buying the 1.4 teleconverter OR going the 80-40 f/4.5-5.6. They are both stellar lenses from everything I've read. The 70-200 has particularly beautiful clarity and contrast, and I've thought that when I'm not photographing wildlife, I wouldn't really need the longer focal lengths of the 80-400, and when I needed the extra focal length, I could throw on the teleconverter.
I have both. The best combo is the Nikon 300mm f4 VR PF with the TC-14. Of the two you mention, the 80-400mm VR (second version) is better than the 70-200 with TC. Neither are as good as the 300mm f4 PF with TC-14.
Agree with Two23. Have the 70-200/4G that I got after haven given up with the 80-400G. I've used the 300PF but not used it extensively, but my shots turned out better than I expected. The Sigma 100-400 C is in my book far better than the Nikon 80-400G, alas not perfect, as it focuses slower, and isn't dust-proof. But a delight in every other way, especially the price (bought it new, full price, at about 25% of the cost of the 80-400G)!