Wow. Just wow. Finished the tutorial regarding HDR ghost removal as well as the one on "surrealistic" options. CS5 is just amazing.
Now, please don't get me wrong, but the ability to remove ghosts is as important as keeping them in. Why...solves out of registration issues. The plus side is if you want them there you can keep them there by simply not checking the remove ghosts box...that way objects in motion can remain in motion as a blur and ghosted if its important to the image.
This file was one I knew that had a lot of loops to toss at CS5 to see how well it would handle a variety of issues. Simple drop downs and I had a "surreal saturated high contrast" image and the ghost tool removed the moving cars that otherwise were blurred headlights streaking by. Changes the whole feel of the picture to have cars simply frozen in time and the blurs removed. It was just an experiment, but I liked the results.