Need to upgrade my Nikon to something a bit better

I have had a Nikon D40 then upgraded a year or so ago to the D70 and now i'm looking at changing again. I love using a Nikon but my budget isn't huge as i spent a ton on my lens. I'm looking at either a D200, D90 or the D3100 but not sure which one to go for? All around £200 to £300 which is within my budget.

The D90 will be the best choice, especially if you have any AF lenses.

I went from a D70 to D90 and now to the D7100. The D90 is a fine camera.

300 pounds will get you a used D200 body, maybe a 18-55mm lens.
The D90, D3100 are out of the question at the price.

Keep saving. You are barely getting anything better with the money you have.

whatever you do, do not buy a D200. The sensor is old and it's going to be just as noisy in low light/high ISO as what you have now. The only advantage that the D200 has is the semi pro build of the body. Save up for a used D5100, it has the same Sony Exmor image sensor as the D7000, aim for that one.