Focus point wrap around -- what is it? What does it do? When should one use it? I was watching a tutorial on shooting action shots and the person in the video said you should turn it on.
First of all, don't do something just because someone says that you should. Give it a try; if it works for you, great. If it doesn't work for you, don't feel that you "should" because someone else said so. It's that kind of thinking that has so many people applying Clarity to portraits because they read about it in a Scott Kelby book.
In Single or Dynamic AF Area Mode you can move the focus point on the camera by using the multi-directional pad on the back of the camera. Without wrap-around enabled, you can't move the selection any farther than the edges of the frame. With wrap-around enabled, if you try to move a selection point beyond the edge of the frame it will jump to opposite edge of the frame.
Also the person in the video said to put the focus on Dynamic Area for shooting action shots. Would there be an advantage or disadvantage to use Dynamic Area over Single Point focus on any given day under various shooting conditions? What exactly is the difference between Dynamic Area AF vs Single Point AF? I know Auto AF is when the camera automatically selects what it thinks the focus should be, right? I would have thought that for shooting something like a skateboarder in the video, that the person would have used 3D tracking, but he selected Dynamic Area AF instead. So when would one use 3D tracking -- for shooting a car or airplane?
Again, find what works best FOR YOU. Don't do something because someone said that you should.
Single Point Area AF Mode focuses only on the point you select. The focus point doesn't move. Dynamic Area AF will start off focusing on the point you select, then if camera thinks that the subject moved, it will shift the active focus point to one of the points surrounding the one you selected. Depending on your camera, you can select how many of the surrounding focus points it will use. For example, on the D300, you can select 9, 21, or 51 surrounding focus points. So, if you selected 9, the camera would use the focus point you selected as well as the 8 focus points surrounding it to track the subject. The fewer dynamic points you use, the faster the camera is supposed to be able to track the subject. However, if the subjects is really fast and erratic-moving, you might need more focus points. The problem I have with the regular dynamic Area AF in the current batch of cameras is that it doesn't illuminate the shifting focus points when it tracks the subject. It only shows the point you originally selected. That's why when I use Dynamic Area AF, I use its most advanced setting, 3D tracking. In 3D tracking it uses all 51 focus points to detect and track the subject's distance from the camera, its movement around the frame, and it actually shows you where its tracking by illuminating the active focus point. Sometimes when you have a static or slow-moving subject, dynamic AF and 3D tracking keeps moving focus points, looking for a moving subject (kinda like using VR on a tripod...don't do it). In those situations I prefer to use Single AF. 3D tracking isn't a miracle, and you may find it to be a little slow on all but the D3 and D700.
Also while I'm at it, I may as well ask - Center Focus Point Normal Zone or Wide Zone which do you choose and why one versus the other?
I think you're talking about Live Mode AF here. Normal just uses the focus point and Wide uses an area a little larger than just the focus point. If you're hand-holding, wide might work better, but see what you prefer by actually trying out both modes in different conditions.
Okay a couple more -- Do you use Long Exposure NR or High ISO NR why or why not?
This is a tough one to answer; you'll have to try it out and see whether you like the results. I prefer the advanced algorithms of post-production software for noise reduction. I shoot mostly RAW and I use low ISO and a tripod for long exposures, so in-camera noise reduction is of little use to me. They might be more useful if you shoot jpg and don't want to do a lot of post-production. However, they will practically double time of your exposures. So, if you take a 30 second exposure with noise reduction enabled, you might have to wait up to a full minute before you can take your next shot.
I've been shooting with NR off and I think High NR set to low, IIRC. I turned off High NR tonight. Decided I should see how the pics turn out without any in camera NR applied. 
