Very good questions.
I don't have much time but the short of it is that I always use AEB. So depending on your camera, I have Canon XT, so I have a 3 shot AEB system that can range up to 2 step offsets (-2ev 0ev +2ev). I usually go with this for most daytime scenes that do not include the sun. Anyway here is a real detailed and informative link on HDR:
Bracketing & Number of Images « Before the Coffee
Have fun.