Personally, I would go with the D200. I think you always have to consider exactly how you will use your gear when contemplating a purchase. I too, shoot outdoors and near the water quite often. There is no way I would invest in a cheaper non-sealed camera because I know what risks I will be exposing it to. If you drop $1k on a D70s and kill it in six months, you're back to the drawing board. To me, I think it is worth it to hold off until my budget afforded me the ability to purchase the correct tool for the job. I shoot a D100 and now a D2x. I have also shot with a D70 in the past and did not care for it much. Another big factor to me is metal vs. plastic body. The D70 felt like a toy and I was afraid to hold it. I travel a lot and know that my camera bag is going to bounce around in overhead bins on airplanes and on bumpy rides down gravel roads. In addition to the seals and the metal body, the D200 is a lot more camera for a fairly small cost increase - all things considered of course.