Here’s a highlevel comparison of the new Canon 30D with Nikon D200:

• Canon 30D has 8.2MP versus Nikon D200 has 10.2MP
• Canon 30D spot metering at approx. 3.5% at center of viewfinder versus Nikon D200 at 2%
• Canon 30D AF Working Range EV -0.5-18 (ISO 100 at 68°F/20°C) versus Nikon D200 at EV -1-19
• Canon 30D has 9 AF points versus Nikon D200 has 11 AF points
• Canon 30D JPEG max burst high-speed at approx. 30 frames (Large/Fine) versus Nikon D200 burst depth of 37
• Canon 30D RAW max burst RAW at 11 frames versus Nikon D200 burst depth of 22
• Canon 30D does not have GPS versus Nikon D200 built-in GPS
  
• Canon 30D viewfinder magnification of 0.9x versus Nikon D200 at 0.94x
• Canon 30D ISO settings has two zones, Basic Zone: automatically set by the camera; Creative Zone: equivalent to ISO 100-1,600 (ISO speed can be expanded to ISO 100-3,200) versus Nikon D200 has ISO settings of 100 to 1,600, also pushes to 2,000, 2,500 and 3,200 and has an AUTO setting
• Canon 30D ISOs are settable in 1/3-stop increments verus Nikon D200 are settable in full, 1/2 and 1/3 stops
• Canon 30D exposure has bracketing range of +/- 2 stops in 1/3- or 1/2-stop increments versus Nikon D200 with 2 to 9 exposures in increments of 1, 2, or 3
• Canon 30D has metering range of 1-20EV versus Nikon D200 2-20EV
• Canon 30D eyepoint is 20mm versus Nikon D200 19.5mm
• Canon 30D Diopter setting is -3.0 to +1.0 versus Nikon D200 -2.0 to +1.0m-1
• Canon 30D has image protection versus Nikon D200 does not
• Canon 30D supports direct printing from camera versus Nikon D200 does not
  
• Canon 30D is lighter at 24.7 oz./700g (Body only) versus Nikon D200 830g (without battery)

Website : Canon 30D product specification information

Website : Nikon D200 product specification information