Thanks for your replies. Can't afford a Nikon 200-400. The 70-300 Nikon VR is interesting but just read a review by Ken Rockwell that has confused me. He says this is all the lens you need and then goes on to say that its over priced, plasticky and made redundant by the Pro 70-200VR f2.8. Am I missing something here? Read good things about the Pro 70-200 f2.8 VR but its very expensive. Is there much difference between 200 and 300? Will 200 be enough of a zoom? What about the cheaper 18-200VR?
Haha!
Ken Rockwell confuses a lot of people. I like him, and if you know where he's coming from, he makes perfect sense. If you don't, he can be a bit difficult at times.
There is no way you can compare a 70-300 VR with the 70-200 2.8 VR - it is huge and costs a bomb. What you are paying for, and carting around, is a low f/2.8 aperture which most people really don't need IMHO. And the pro build quality, but the 70-300 can hardly be described as plasticy. And the 70-200 obviously doesn't compare at all at 300mm, with is a 50% increase (which is the way to compare). If you look at pictures taken with the two lenses where they overlap, ie 70-200mm f/4-4.5 or so, they will be pretty much indistinguishable - if there is any difference, 10:1 it will be user error.
The Nikon 18-200 is a different animal. It's an all-in-one lens with an amazing range, but it is compromised in all sorts of small ways. It's also pricey and heavy/bulky and I think suffers from zoom creep (lens extends by itself when pointed down) which has been fixed in a revised version just announced.
Having said that, I think that lenses like it are actually pretty good in the important areas and if you can put up with a bit of colour fringing at the edges (CA), some vignetting and barrel distortion at the wide end (most of these things can either be reduced or eliminated in post processing) then you've got a very potent package. These lenses don't seem very popular on here, and since I don't have one I guess that says where I stand, but I can see the appeal.
You need to get your hands on these lenses. They are very different. Personal choice.