I still really like Unity, don't get me wrong, but it'd be nice, sometimes, to be able to slather post processing on everything without breaking a sweat. Here are two UDK levels that are really awesome looking and don't rely on the default UDK assets, which is so much of the UDK stuff I see out there. (I also wish Dead End Thrills would feature indie work more often, like, 99% of the time.)
Animal Memory (Test 01), by Jack "Gauss" Monahan. Download here. Find all the pink cassette tapes, just like the cool kids in Tony Hawk games. My critique to him -- it's so postmodern cool-looking that I found the level very difficult to navigate. Masterful use of color and silhouettes though, of course. Next build, I believe, Mr. Monahan plans on adding mans to shoot.
Hubris, by Andrew Yoder. Download here. Not much to do here, other than walk around and be freaked out by the ambient sounds. He cites me (oh dear) and Dan Pinchbeck as his inspirations. The models and forms are technically very simple, and sometimes that's more of statement than fancy cubemapped parallax stuff. It's like Ico HD on acid.