hi tom, yeah when i do hdr images i always use photomatix pro , it is the best. not sure if many folks realise i very rarely use it on my rock art shots as it can give a weird texture. the shots from cairnharrow are staight from the camera with some saturation added.
A lot of folk seem to use photomatix. Personally, I think you can get better results using camera raw/photoshop and tweaking contrast, saturation and fill light - then over laying layers to bring out detail. Avoids that horrible flat look that a lot of HDR seems to have.
Have you tried doing it the gnarly way in CS2 (or later, dunno version what they're up to these days)? Doesn't work from a single RAW like photomatix, but I seem to recall there's a bit more control over things. Such as getting a full 2d curve profile instead of a linear slider.