I've got a 55-200mm and it's fantastic - dirt cheap, great sharp images, VR, the works. However, times change and I'm looking for something a bit more flexible. The options that immediately spring to mind are:
70-300mm VR ~£400
18-200mm VR ~£450
Sigma 70-200 OS f/2.8 ~£850
Keep the 55-200 and buy a 105mm macro
I managed to break my kit lens a couple of years ago (concrete slap) and currently I'm using a much loved Sigma 18-50 f/2.8 as my standard zoom which is fantastic and goes with me everywhere. People seem to be raving about the 18-200 in that you don't need to change lenses again, etc, etc. The downside is, obviously, it's not a particularly quick lens. VR may get what.. 2 or 3 stops out which is a bonus. It looks like a decent walkabout lens, something that I can slap on the camera and just go and take pictures without worrying about taking multiple lenses.
The 70-300 would be a simpler upgrade - better optics and longer reach.
The Sigma is also on my mind, along with maybe the Nikon 80-200 AF-D. I've been eyeing up a fast telephoto, something that I can use indoors and at gigs, that sort of thing. The downside is that it costs an absolute fortune and I could buy the 18-200 and another lens for the same money. I could buy many other things with that sort of money!
Soo... I'm not really sure what I want. The 18-200 sounds like a fab lens, but I'm concerned I'll miss out on the low light performance I've gotten used to (I've basically been shooting on f/2.8 glass for the last year). On the other hand, I was considering getting perhaps the 18-200 and a single fast lens like a Tokina 100mm.
The Nikkor 105mm looks lovely, and would be conveniently dual purpose, but I'm not sure I can afford to shell out quite that much! The Tokina is very highly reviewed, so may be an option...