If cost is the primary issue how about a used D200/18-200VR?
Interesting you should mention both of those.
First thank you to those who have suggested purchasing used, but I am leary of doing that re a computerized, electronic device, generally.
I love the D200 body. I was interested in the Nikon 18-200mm. My old 35mm stuff, some of which I still have, was pre-AF manual nikon bodies and glass. I also liked their enlarging lenses. So actually, my "predisposition" is towards Nikon.
I have done a fair amount of research on lenses relevant to my interests, and that Nikkor zoom was very attractive due to its coverage, and that it would duplicate the coverage of my digital bridge camera. But in looking at lense tests, the Canon one seems to be pretty good for the dollar, compared to others. This is not a slight on the Nikkor, perhaps the shorter zoom range of the Canon accounts for some of its quality.
Like I said before, the the 17-40mm @ 1.6x crop also matches the range I usually "think" in, in landscape. The similar nikkor glass would be my first choice, due to my predisposition, but for its higher cost.