I bought a 5d to replace my K20d and kept the K2000 for a small carry camera and for my wife who loves it.
I am split, because I really don't need full frame, and really don't need a new camera, but if I were to sell one I would sell the Canon 5d, and buy the K7. I might do this because having two lens mounts drives me nuts.
Here is why. The K2000 uses a CCD sensor that is great at low ISO, and at high ISO doesn't have the crosshatch noise that is so common on the CMOS sensors when push processed due to how the ADCs are on the chip and read out. It works great for high ISO B&W conversions, etc.
The two would compliment each other. With the K20d there is really no complimenting. The K-7 would be better in most ways and there would be little reason to use the K20d any more (except as backup).
I would sell the K20d and keep the K-m/K2000 since they compliment each other. Or you could just sell all of them and buy the K-7 too, as already mentioned. It is a bit smaller than the K20d but keeps all the features. I love the K-m but get annoyed by the lack of some features.
Eric
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