Image A is NO HDR. D300 Active D-Lighting to recover as much highlight/shadow detail as possible with a single exposure. This is my "baseline".
B, C, & D are 3 of a host-of-infinities of possible HDR outcomes. HDR is way more art than science at this stage (of its evolution and my expertise).
B - Photomatix "Blended Exposure". Very straightforward without a myriad of sliders to tweak. Provides a "photographically natural" looking result.
C - Photomatix Details Enhancer tone mapping option. This is where the infinity of infinities options reside. Very powerful but easier to generate a "cartoon" than a natural looking photo (at least for me at this point in time).
D - output from Essential HDR (one of a bunch of Photomatix competitors). I am able to get decent results from this program much easier than with the Photomatix Details Enhancer because the sliders are less numerous and their effect is easier to visualize.
All of the images shown would benefit from post-processing after the HDR image is created. Apparently, post-processing is a necessary evil because of common difficulties when generating HDR images (halos being an often cited issue). Image A (non-HDR) has true colors - the rest all have a cast of one shade or another.