Some good info some stuff thats pretty frustrating, I am sure of it has been addressed, so if i retread forgive me.
Sensors do not fail typically, shutters do, that's the mechanical, the electric sensor will rarely be a failure point.
For a good statistical comparison of any DSLR's i like this site: http://snapsort.com/compare
Canon does not produce better colors, some canons produce better colors than some nikons, some nikons produce better colors than some canons. There is no one rule that applies to all nikons or all canons.
Canon lenses are not cheaper, some canon glass is cheaper compared to equivalent nikons (50mm f/1.8), and some nikon glass is cheaper than some cannon (35mm f/1.8). But 3rd party glass (sigma and Tamron for instance) is typically priced IDENTICALLY for either mount.
But thats only statistical. The feel of your camera and the layout is pretty important much like it might be on a car, so holding and shooting a lil bit with what you think your going to buy is paramount.
I would also ask, do you have a friend with a DSLR of a specific brand, the ability to learn from someone with the same system is huge, and borrowing glass is nice as well.
Mega Pixles do not matter, a 6.1MP DSLR can print up to 8x10 easily so unless you plan to PRINT bigger than that, ignore MP count, it really is the least important statistic unless your talking about DOUBLING the MP count.
Keep in mind that double the MP does not double the reoslution, to go from a 4x4 square of pixles has a total reoslution of only 16 pixles to double the size to a 8x8 square of pixles means you now have 64 pixles. You have to think in 2 dimnesions.
For AutoX you will rarely need really fast glass or a big ISO bump, your outside, unless it is raining, stupid early in the morning, or stupid late at night, you will have plenty of light.
Now my opinions:
You can make great shots with either camera. I shoot nikon, i love it, i have shot canon, i still get good shots, much like a driver the photographer make the difference here....
I feel that in a given price range canon puts more effort into the MP count that other factors that matter like ISO performance, color depth, and EV range. As I stated there are exceptions to this rule going in canons favor but overall i think Nikon are more about the end product, canon plays the numbers game better. If you would like I can give specific examples of this but it is unnecessary because of the following FACT.
The cheapest new DSLR you can buy today was TOP OF THE LINE a decade ago, the nikon D3100 is a $600 camera and 10 years ago would have been worth $10,000 given it's relative performance, so buy what you like, and what your friends have and what FEELS GOOD in your hands.