I have actually owned both these and both are good, but they are old technology now as things move that fast.
The D90 is a 2nd generation Nikon sensor, this sensor is the same in the D300, D300s, D3000, D5000 and D3100 this sensor is made by Sony which is what they use believe it or not !! and is also used by Canon.
The D200 is a 1st generation although a better built camera the D90 is superior on image quality.
If you find the extra money purchase the new D7000 which as superceded the D80/D90 range, the new D7000 is a 3rd generation sensor and is the first in the Nikon range to use it. The D7000 is a DX camera which actually gives you an FX view finder what you see is what you get.
But if its a choice D200 or D90, the D90 wins hands down.
If you really want to consider saving money i would look at a D40 my 12 year old son uses this most and it is incredible. I think nikon discontinued it twice and brought it back into production due to popularity. It will only take DX lenses though but my son has taken better photos than me with this !!!! On Ebay you will probably pick a body up for £150.
Look at these sites and browse the information.
http://www.kenrockwell.com/index.htm" onclick="window.open(this.href);return false;
http://www.bythom.com/nikon.htm" onclick="window.open(this.href);return false;
Spring
(Electronic Engineer)
D40, D80, D300s, D7000
