Hi Nawty... Yes, that was my eventual conclusion. The increase in ISO capability might (perhaps) be useful one day but I have my doubts. In all other respects it's probably just as well to put the money into some better glass. Currently I am mostly using a Tamron 18-200 f3.5-6.3 as my 'go to' lens but also have a Nikkor 18-70 f3.5-4.5, Nikkor 50 f1.8 and Sigma 70-300 f4-5.6.
My main interest is urban shots, candids of people at events and a little sport. The 18-70 is a good lens but too short at the telephoto end for candid work - I'm not one of those 'in your face' people, I prefer to stand off a little to get my shots and changing lenses back and forth between the Sigma and the Nikkor in this type of work is a right pain - I know that I have missed several shots that I would have liked. Now the Tamron 18-200 has been good but I'm not really happy with it in terms of sharpness so have decided to upgrade and rather than go for another independent I thought I'd look at the Nikkor 18-300. My thinking is that the 18-300 plus the 50f1.8 would cover everything I need and the cheapest I can find for a new lens from a UK supplier is £425. I've got some money saved and if I sell off the 18-70, the Tamron and the Sigma I should be just about there in terms of cost.
Alternatively, and only about £100 or so cheaper, is the option of the Nikkor 18-200 but I'm not sure if saving that much and not having the extra 100mm on the long end would be a false economy, so I'm still leaning towards the 18-300.
Rob