Overall Image Quality / Specifics
When first announced we were interested to learn that the D200 utilized a CCD sensor, the assumption had been that Nikon had switched to CMOS sensors with the advent of the D2X. Not so however, and according to Nikon they select the sensor to match the intended function of the camera. From a noise point of view the D200's CCD sensor / electronics performed similarly to the D2X, that is to say close to Canon's benchmark CMOS sensor up to ISO 800 and then requiring more noise reduction as sensitivity increases (so much so that we loose detail to NR). One measurable difference between the two cameras was dynamic range, the D200 exhibitting about half a stop (0.5 EV) more dynamic range above middle gray than the D2X.
Other noteworthy items were in-camera sharpening which is at best 'conservative' and at worse detremental to the visibility of fine detail (which is actually there, and has been captured by the sensor). The limited range of image parameter (or 'image optimization') adjustments makes it more difficult for the photographers to tune this out, without shooting RAW of course. I also found the camera to be far more conservative with its metering, requiring at least a third of a stop (+1/3 EV) of compensation to produce a good coverage of the tonal range (although this could be the calibration of my particular camera).
Not long after the D200 hit the shelves the first few early adopters spotted a potential problem which was quickly coined 'banding' or 'vertical banding'. This appears in the shadow areas of images shot at high sensitivity and is due to a calibration issue somehow connected to the amplifiers behind the sensor (while Nikon has acknowledge the issue we're still not 100% sure of its cause). It's remarkably similar to the banding issue which affects the Canon EOS 5D (although this is connected to electrical interference in AF servo mode). Several of our forums members have had their cameras 'repaired' by their Nikon Service center (click here for an example of a before and after).
Now I like nothing more than finding an issue with a camera and investigating it to the nth degree, however I personally didn't experience this problem with the D200 I had for review (and it was an early batch camera, one of those which could be affected). After searching through the 1500+ images I shot with the D200 I couldn't find a single good example of such banding, it's clearly a very individual camera issue. Hence the only advice I can give is read our forum, check your camera and if you believe it is affected then contact your local service office who will deal with it for you.