I've had a Nikon for 41 years. Well, not "a" Nikon, I started with the Ftn, then F2, F3, D80 and now a D7000. I'll admit to a bit of brand loyalty, but I've never been one to slam Canon ... a good number of my friends shoot Canons and produce wonderful results with them.
Back in 1969 I was looking to replace my Fujicarex, an odd little SLR with a leaf shutter and interchangeable front lens elements and a focusing wheel where Nikon's main command dial is today. At that time and indeed for the previous decade, Nikon had been the pinnacle of aspiration for those with serious camera lust. Looking at the cameras on the sidelines of any sporting event, Nikons were even more common than the white-lensed beasties are today, they truly dominated the pro 35mm market (except for a few rangefinder addicts who carried Leicas). Browsing the pages of Popular Photography, Modern Photography and Camera 35, I always lingered on the Nikon ad, thinking, "Someday."
Eventually, I lucked out... my high school art teacher had a friend who'd just returned from Vietnam and had bought two SLRs over there... a Canon and a Nikon. He had decided to sell the Nikon (an Ftn) because he felt it was the more complex of the two and wanted something simple. So I bought the Nikon with money borrowed from my college fund. My parents groused a bit, but I was planning on majoring in photography... I suggested (well, whined, really) that I should have the proper tools, and they relented. I've often wondered how much my photographic experience would have been altered over the years had that guy decided to sell the Canon instead.
When it came time to buy my first digital SLR, I tried very hard to be objective... I had a nice selection of Nikon lenses but since none of them were autofocus (and the prospect of manual focusing with my aging eyesight on a groundglass with no split image or microprism was not appealing), I was not closed-minded to the idea of jumping ship and starting from scratch. It was a tough call... being on a budget it seemed like Canon was offering more (on paper at least, in terms of megapixels and lenses in my price range, not to mention the much larger pool of used gear for sale). But after playing with cameras from both manufacturers, the Nikons always seemed to feel better in my hand and had more sensibly placed controls and more intuitive menus. I finally settled on a D80. After wandering around the various forums, I ran across a quote somewhere that seemed to sum up my experience: "Canons are designed by engineers, Nikons are designed by photographers." I'd love to know who came up with that so I could give them credit.
In spite of my brand loyalty, which is probably as strong now as it has ever been over the years, I try to suppress it on those occasions when friends or students ask me what camera they should get. Most of the major manufacturers produce capable machines, and tho one particular body may be a better fit for a particular individual, the most important thing by far is to just get SOMETHING and get out there and shoot... keep the camera close at all times and use it until it becomes an extension of your arm.