I also have the 18-200mm. It is a great walk-around lens. I use it on my studio photography course and it works great because it's sharp at the studio apertures which are typically f/8 or f/11.

And my other lens is a 50mm prime f/1.8 which is tremendously light and sharp. That used to be my walkaround lens before I ordered the 18-200mm. I'll likely still use it though.

I really want a Nikon D700 and a 12-24mm lens though. I can see my bank balance
going down to the tune of £3K as a result.

There are rumours that Nikon are working on VR for the 12-24 and 24-70 so all things are possible. But I think VR is more important at the >100mm range as you say.

Have you changed cameras? You had a D2X, right, which wasn't full frame if I recall.

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stevepa