Nikon vs. Canon is a fun argument to have, but it really doesn't matter. When you buy a DSLR, what you're really purchasing is a commitment to a line of lenses. Cameras are just recording devices. The component that plays the most important role in image quality is the lens. In the Nikon vs. Canon argument, the lens line really doesn't matter, either. They both make excellent lenses, particularly if you purchase the professional-level lenses. Keep in mind that the lenses are what retain their value and are kept for a long time. You'll eventually replace the camera body, but nobody replaces all of their lenses when they buy a new body.
So, what does matter when buying a DSLR body? How it feels in your hand and how intuitive the controls are to you. If you have small hands and buy a large camera body it's always going to feel like a brick to you and you won't enjoy using it. The reverse is also true. A small camera in big hands is frustrating to control and therefore won't be enjoyed. As for the various buttons, my bet is that you will only use a small portion of them. But the ones you do use should be in locations that make sense to you and allow you to manipulate without always having to search for them. Borrow or rent camera bodies so you can try them out. Don't buy what your friends have or what people recommend in forums. You have to like and use the camera you buy so make that decision on your own. By all means, try your friends' cameras to help you make the decision.
Do you need to buy an expensive DSLR to get good images? Not at all. Invest your money in good lenses. Buy the camera body that feels good in your hands and that you can afford. Very few people use more than a small portion of the features offered by even low-end camera bodies. If your camera skills progress you'll know soon enough whether the camera body is limiting your photography. When it does, trade the body in for a more-capable model. Only pros and very, very serious amateur photographers can make use of and appreciate high-end camera bodies. Pros need them because they are built to take a beating in all kinds of conditions and when used to make hundreds of images almost daily. The normal person is just throwing his/her money away by purchasing a high-end body to make 50-100 images a week, at best. Again, spend your money on good lenses.
The most important factor in determining what makes a good image is the knucklehead behind the camera. If you don't learn the principles of photography, composition, and lighting and don't practice, all you'll ever produce are decent snapshots, regardless of how many thousands of dollars you pour into equipment.
Gary
Can't have a post about photography without including a photo, so here's a favorite from several years ago.
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