Funny, you'd think people here would strongly encourage you into the Nikon camp, but I guess we (Nikonians) aren't into the "hard sell." The questions people are asking you such as "what are you missing with Canon?" etc. are fair questions - and only you know.
My background is that I started back when the F90 was a popular film camera. Somehow I talked myself into a full Canon film system. I felt at the time that the Canon film body user interface made more sense and I had an impression that Canon was technologically more resourceful as a company. So I wound up with a Canon body and some USM lenses. After a while I found the user interface thing was less interesting to me than the look and feel of the photos. Increasingly, I developed the opinion that the camera/lens system of each manufacturer produced a certain "house look and feel". In my opinion, the Canon house look and feel was good, but different than the house look and feel that Nikon produced. All this was in the film realm. From there I began to wish that I had gone for what I considered to be, in my own subjective world, a more "accurate and realistic" photo IQ that Nikon's film system produced - but I was stuck with the investment in the Canon body, a flash, 3 USM lenses, and various accessories. So, I just lived with the Canon, while wishing that I'd had chosen Nikon.
When the first DLSRs came out I figured it was pretty economically clear that I needed to stick with Canon; but when I tried their DSLR body, I didn't like their user interface (I think they probably hadn't quite refined the early DSLR user interface as well as they had their film body interface or as well as they have refined their newer DSLR interfaces.) But what really had me in a quandry was that despite the fact that you can theoretically make a digital photo look however you want (WB, etc, etc, etc.), the house look and feel of the Canon digital images looked just like the Canon film images - and by that time I was sure I had a preference for the Nikon house image look and feel. Well, I bit the bullet and sold the whole Canon system on eBay; it was a bit of a loss, but I had kept my gear in perfect condition and I did ok - and I was free to move to Nikon.
I started over with Nikon glass and a D100. I found the user interface to be satisfactory, the camera to be just a tad slow in response, but ok - and mostly what I got that I had been seeking for several years was the Nikon image look and feel. I just prefer it. Having said that, I'm sure I could be stumped if you just put a pile of photos in front of me and said - "sort the Nikon photos from the Canon photos". But there is nonetheless (in my opinion), something about the out of the camera image look and feel of Nikon photos that I find more desirable - I can't express it well, and I certainly can't define it or specify it, but I just know what I like. And there is something about the equipment itself that causes me to favor Nikon (not for all products or all features, but on balance). This is not a knock on Canon - it's a great company with lots of great products.
Long story short, there is something personal about photography and photography equipment and when you are comfortable and happy with your gear you can start to get past the gear and focus more on how to capture photos that move you and the people you photograph and the other people who view the photos.
So, I say: Hey, come on over to Nikon - I'm happy I'm here, I can very much believe you will be happy to be here, and I think the more users we have the better Nikon will do and the more Nikon will be able to do what they do well - which is to serve the intersection between what you can measure and what you can feel.
Happy DP,
Yada
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