For Photomatix fans and users, version 4 has been launched (28 Sept 2010).

The site is:

Changes include:

# interactive anti-ghosting (looks fun to use and has in-built tutorial);
# noise reduction prior to merging of images;
# thumbnails of preset (Photomatix and user-defined) tone-mapping options - very useful for a quick look;
# new fusion blending (at least I think it's new, certainly the lay-out is).

Overall, looks like some good enhancements.