Bad_Blood, with regard to longevity there are two aspects:
- Is he body sturdy enough to live to 100,000 shots and all the banging around that you might throw at it in the lifetime? I think in this respect the 40D and the D200 are basically equal.
- Does one body become outdated faster than the other? Well, Canon has the lead here as the 40D is brand-spanking new and the D200 will be superseded by the D300 soon.
So without looking to deep into the feature-set that you
need, body-wise the 40D has a lead.
But from all gadgets that contain a lot of electronics plus some critical moving parts you come to expect an update-cycle of the manufacturer from 12-18 months and from critical users around 2-3 years.
If you look into the whole system (incl. lenses and accessories) the longevity of the body is decreasing in weight as the major invest in lenses will not be obsolete too fast.
Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews
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