Thankfully you have the good sense not to ask which is better. =)
I like Canon - I'll be honest - because my cameras are Canon. And lenses and such. But I invested in Canon for these reasons:
- There are over 220 lenses, and about 30-40 with IS, offered by Canon. While I'm not sure about Nikon's exact number, I know it's a heck of a lot more.
- Canon's cheaper than Nikon in macro lenses
- Produces a wide range of cameras; and has the best comprimise between Sony's image quality which is the best, and Nikon's ability to deal with low noise at high ISO, which is the best - so, Canon's in the middle and overall is the best
- Wide variety of accessories, more than any other brand, and generally cheaper
Why Canon isn't great:
- IS in lens, while producing a better image and making the effect visible, is a lot more costly
- Sometimes L lenses are better, sometimes ordinary USM lenses are better! It depends, and that's when you get a bit stuck... but this isn't really big
- Somewhat limited in IS lenses
- EF-S lenses can't fit on non full-frame cameras, or APS-C, only EF can, and of course this is more expensive (this doesn't happen on Nikon because its full frame cameras crop to 1.-x factor (whatever suits the lens) to be able to take the picture like an APS-C sensor would be able to
- Canon lenses are expensive besides for its macro lens range
- Its cameras tend to be a bit more expensive - in the case of pro, the 1Ds is the most expensive, although rated the best in most reviews
Doing some research some time, when I first decided, I checked out this:
http://photo.net/equipment/35mm/canon-v-nikon
And it helped.
It's all about what suits you, if you're interested in buying one.