Originally Posted by AA25

When you buy into the Nikon camera system, you might be locking yourself into comparatively low resolution. Nikon does not make their own sensors, and their sensor supplier, Sony, is now a competitor. Nikon does not have a full frame (35mm) digital sensor, and Sony will probably not give it to them if Sony develops one. Canon makes their own sensors, and already has full frame cameras. That means you have an upgrade path for the 30D that Nikon lacks. That's important if you get some high quality lenses and accessories for the camera.