Even though these programs are powerful and offer almost endless creative options, you will find that exploring additional black-and-white options open up additional creative possibilities. I say "additional" because you can desaturate an HDR image to create a black-and-white image.
One reason for the added creative options in black-and-white imaging: When you remove the color from a scene, you remove some of the reality. When you remove some of the reality, your picture can look more artistic and creative.
Here are two examples of black-and-white HDR images. Both images were original created in Photomatix from color files. To create the black-and-white effect, I used Nik Software's Silver Efex Pro plug-in.
Back to Silver Efex Pro. You'll find several cool Presets, which suggest starting points for your images. One is Antique Plate, illustrated below. After selecting a Preset, you have many other creative options, including which color digital filter to apply to an image, shadow/highlight control, brightness, contrast, and of course, control points.
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If you have CS5 (or CS4), other options for creating black-and-white images are available in ACR (under the HSL tab) and as a Black-and-White adjustment (use an Adjustment Layer).
Have fun creating your black-and-white HDR images.
Explore the light,
Rick