2 Mac apps that do pretty much the same thing; let you browse around on Flickr without actually having to go to the Flickr website.
Photonic was just released. Exposure is in testing. Exposure (will?) also has a neat rearrange thing that tosses photos around. Check out the video.
If neither of them has iPhoto or Aperture integration for uploading videos they become somewhat pointless. Photonic is cool, but no way is it worth $20 right now to me.