Just one comment on XYZViper's shots. I don't really like panning the way a lot of people do it, keeping the whole subject perfectly "clean", so the rest of this post is purely my (probably minority) opinion.
I understand why people do it, but at the risk of stating the bleeding obvious, you lose something that's important about what you're taking a photograph of - the
movement of the car (or bike). There are situations when it's desirable to really see the car clearl, for example if you're really interested in the details of the machine, but if you're interested in photographing the "experience" of watching the bike/car go by, some blurring of the machine would be better, in my opinion. Coincidentally, Nellis has a few shots on his Flickr illustrating what I mean, for example "IMG_5854.jpg". There's still some blurring on the car's rear end, that suggests movement, the pan blur adds to the sensation of speed, but you can still see the car clearly.
Having said all that, I really like the first one
No idea why, whether it's the B&W, or what, but it just works for me in that "experience capture" sense. It could have done without the other car on the left, sure, but then on the other hand that also adds to it (depends what one considers the "subject" to be, I suppose - is it the Porsche, or is these two cars passing one another?).