Hi RBG,
I've recently upgraded from a D70s to the D200. I wasn't ready to upgrade but a close encounter with a rock and my D70s forced me to upgrade
I know that reason rarely gets in the way of gear lust, just look at what I have in my camera bag, but one thing you should ask yourself is what is it that the D70s does not do for you?
Okay back to answering your question:
-more rugged body
-mirror lockup for long exposures
-used CF cards instead of SD, as per the D80
-easier access to controls
-worse battery life (not good
)
-higher rating on shutter
-semi-pro
-better colour rendition
-lots of other extras that I like but that wouldn't make me switch
Love my D200 but as I said, I was still very happy with my D70s. You may also want to consider the D80, very similar features to the D200 but in a D70s package.
HTH,
André