I have HDR rendering in my games, not sure if that is the same thing as what Curt mentioned, but if it is then I can also say that it makes a huge difference in the way images look. I have quite a few desktop wallpapers in my game screenshot collection that I use, and all of them have HDR lighting in them. You really notice the difference.
Also, an update to my desktop - I don't show icons much anymore due to my shoving programming stuff all over the desktop, so all I have is my ObjectDock Pro (awaiting the next version of CircleDock!) and the taskbar.
The background is an edited screenshot of my (favorite) game, Project Torque. I was drifting in my Subaru and decided to make an ad out of the thing based on the new TV commercials (I love the car, it really is fun to drive, regardless of being "simulated").
(The PNG was over 2.2 some odd MB, hence the JPG image format)
EDIT: That image does have HDR in it, although a bit hard to notice due to the effect wearing off with time (as to simulate the human eye adjusting to light).
EDIT 2: I need to post my Xubuntu desktop too, don't I?