The Android developer's challenge has release most of the top 50 (a few opted to not be made public for now). A slide deck of the winners is available here. I've gone through some of them and they have been blowing me away. Lists are being put together with the websites for the winners. There is some really exciting work being done.
Even though its the first one on the list, AndroidScan still blows me away. It uses the phone on the camera to take a photo of a bar code, look up the product in a database, and then gets you all the information you would need about that product and where you can buy it right from your phone (amazon, ebay, etc). Do yourself a favor and watch the video.
I'll be going through that slide deck and will be posting some more of my favorites. Anyone else hope the HTC Diamond can run Android out of the box? ;)