I think you make a great point here. I think the main reason we have witnessed 'obsolescence' in digital cameras, is that it has taken 10 years or so for the 'film' component of the cameras, in other words the sensors, to become equivalent in quality to film. Many would argue we have now gone beyond the quality and versatility of film. I do think we are now back where we were with film cameras in terms of cameras becoming obsolete - in terms of taking extremely high quality images, in almost any reasonable light, and being able to enlarge them for almost any purpose, the D7000 will never be obsolete. Cameras will add 'must have' features, merge video with stills etc, but otherwise not become obsolete until for some reason one is no longer able to transfer the images from the SD card, or when SD cards go the way of Kodachrome. Yes, only now are film cameras starting to become truly obsolete.
Just because I want to be "contrary"
I have to disagree with that statement. One common definition of obsolescence is: Outmoded in design, style, or construction. Another is:out of use or practice; not current. Cameras being mostly computers these days are still very much subject to "Moore's Law" - The number of transistors that can be placed inexpensively on an integrated circuit has doubled approximately every two years. The camera you will be buying 5 years from now will be DRASTICALLY different than the one you have today. There's a good chance it won't have a mirror. It will probably have 250,000 ISO capability. It might be 48mp. It will have 120fps video and 32bit color. It will communicate wirelessly with your new Macbook Pro (the one you have now will be obsolete, yes?) You want to keep your old camera when that one is available?
I'm not saying you won't enjoy shooting an older camera. My wife uses my old D70 and occasionally confounds me with the excellent photos she takes, but is it "obsolete"? Yes, it is. I have a photography friend who told me two years ago 12mp was the upper end for DX and there was no way it could go any further. Well, here we are...
Loftus, We'll come back to this discussion in 5 years and I'll check your Sig out and see what equipment you are using. I am certain it isn't going to say D-700 and D-7000 anymore because there will be two bodies that are radically better than what you are using now and there is no way you won't upgrade because you obviously enjoy the "latest" technology. What you have right now, will be in your mind -- "obsolete". However, that 60mm and 105mm Nikon macro lens will likely still be not only viable, but desirable.
Heh.
JP