When choosing between brands of camera, I feel that it is more important to examine other factors beyond the features within one particular model.

Canon and Nikon have different ranges of lenses, accessories, and 3rd party add-ons. They also take slightly different approaches to their ranges of cameras. Canon, for example, has a much broader selection of lenses, with inexpensive lenses up to top of the line pro lenses, and everything in between. Nikon does not have as broad a range, and there is less distinction between its high end and top of the line lenses. Both have good 3rd party support.

As for camera bodies, these seem to mirror one another, though Canon seems to be the more prolific of the two, and appears to be focusing on frequent updates to the lower end of cameras. The benefit is that Canon's lower end models tend to get dramatically better over time. I would rate both Canon and Nikon equivalent here.

Both have good selections in flashes and other bits, but all Nikon cameras support off-camera remote flash, whereas with Canon, only the 7D at the moment supports this feature. Canon has more models with video support as well.

Both Nikon and Canon have a very broad range of 3rd party support, with essentially any kind of accessory being available. This is usually not the case with other brands of camera, such as Olympus and Pentax, where 3rd party selection can be extremely rare.