I want to say practice and a class will get more benefit then additional equipment. I also have a Nikon as some have suggested, but it is an older D200. First weekend out to Road Atlanta with it, took close to 4000 pictures (5fps is NICE) of which 1 came out very good, 3 pretty good, and about 300 that i kept. I was using the 55-200mm VR kit lens, shutter priority, auto ISO. I have since upgraded to the 55-300mm lens, but have not gotten to the track to use it. I think the 70-300 would have been better due to the larger glass, but with my 18-55, i like being able to cover such a large range.
No editing, cropping, etc, just resized for the forums. I am sure I could improve them all with some photoshop time.
My personal best from my own viewpoint.
My favorite in action, though through the fence takes away some.
On friday during monring practice, I got lucky (the driver got unlucky) and I was just beginning to take pictures. I had a very high shutter speed set in order to just try and get some things in focus. I have a series of 48 pictures (that I kept) that show this from the back end starting to step out, until it was hauled away on the wrecker. I was lucky to have such a high shutter speed set, and right place, right time. The impact was about 50 feet in front of me and 20 feet below.
From my research before buying a camera, i looked a lot at both Nikon and Canon. Nikon was the top dog, until i think the 90's, when Canon came out with some new technology in autofocus lenses that was superior to what everyone else had. Many photo jounralists switched to Canon at that time, and with such a sizable investment in lenses, tend to stay with a brand once they make the decision. Nikon has since caught up in technology, and can take just as good of pictures (better in some cases), but the difference is not enough to cause a professional to want to repurchase tens of thousands of dollars in lenses.
Not to be too long winded, but I would say on the picture you posted, it looks a little over exposed. THe lack of definition in the white wall is why i say that, but being so new to this, i could very well be wrong. There are some absolutely beautiful pictures in this thread. Keep them coming!
Grant