I would never suggest, to anyone, that the D200 is a justifiable upgrade from the D80. They both have the same sensor with the D200 having a few more bells and whistles, along with weather sealing and much more durable body.
At least with the D300 you have a better sensor and a far better reduction of digital noise. The D300 is a better upgrade choice compared to both the D80 and D200 with many improvements.
Many D300s shooters are actually converting over to the less expensive D7000 for several reasons, due to this, the price of used D300s are extremely low and some great deals can be had.
The D7000 does have some great qualities about it but keep in mind that it is built for the consumer market, as opposed to the better quality of the body in both your choices of the D200 and D300 prosumer market.
The first question that you must ask yourself is: “Why do I want to upgrade my camera body and will a body upgrade meet that need?”