Ambilight for your PC. That is, LEDs projecting colored light behind the screen in sync with what’s displayed, in order to improve visual comfort while adjusting to what you’re watching. I wish it were hardware-based rather than software (well, the light itself is hardware, obviously — and modular, which is nice — but the software part is bound to be more CPU/GPU intensive than you might like for your games’ sake… and, of course, it’s Windows-only), but it’s pretty cool.
I wonder how they aren’t infringing a Philips patent, though. And, if they aren’t, I wonder why the new iMacs don’t have that yet.