Looking at the D200 Spec Sheet:
Nikon D200 Full Specifications
* DX Format with 12.4 effective megapixels
* The new
CMOS image sensor features high image quality and high-speed 4-channel data output
* New image processing algorithms combine with optimized analog and digital white balance to produce smoother, more consistent gradations with exceptionally pure color reproduction
*
Continuous shooting: 3 frames per second (fps) at 12.4 megapixels for up to 10 consecutive NEF (Nikon Electronic Format) images; 5 fps for 18 NEF images at 6.8 megapixels
* 3D-Color Matrix Metering II with ambient light sensor and 1,005-pixel RGB sensor further improves on Nikon?s acclaimed exposure metering system
* High-speed, high-precision 11-area AF system with
9 cross-type AF sensors deliver quick response and sharp focus, even under the most challenging shooting conditions
* Two new Adobe RGB color modes further expand professional color space options and also support for sYCC color space
* Excellent response with instant power-up and ultra-fast 52ms shutter release lag
*
Top shutter speed of 1/8,000 second and flash sync speeds up to 1/250 second
* Faster read/write speed for the memory card and a
USB 2.0 Hi-Speed interface for faster image transfer
* Large 2.5-inch LCD monitor for easy access to settings and information, as well as clear, flicker-free image preview
* Creative in-camera effects, Image Overlay and Multiple Exposure
* Functions such as World Time, automatic rotation of vertical compositions expand possibilities
* Lightweight, durable magnesium body
* Full support for Nikon?s Creative Lighting System when used with the SB-800 or SB-600 Speedlights
* In addition to DX Nikkor lenses, the D200 supports more than 50 AF Nikkor lenses
* Nikon?s PictureProject software is included, enabling easy control over image adjustment and management
* Support for Nikon Capture 4 (version 4.3), a software application with the tools to assist the professional photographer
* NEF (RAW) format for the utmost in versatile, effective image control and correction
*
JPEG and NEF (RAW) Combination Filing System enables simultaneous recording of NEF and JPEG data for the same shot
I am not seeing anything, aside from the 12.4 MPX sensor and a larger LCD, that the EOS-20D can't do. The 20D has an 8.0 MPX CMOS sensor, and can shoot at 5 FPS, up to 23 images. The 20D has 9 AF points, 1/8000 max shutter, USB2, and can shoot RAW+JPEG.
So, meh
