Google design
Anil Dash made an interesting comment in the most recent This Week in Google podcast, that Google should hire the flickr designers away. I think that suggestion is pitch-perfect: both sites have a minimalist aesthetic, but flickr can be almost a joy to use, whereas Google can be unintuitive and frankly a little fugly.
Design is a feature. I also learned that flickr was developed from a web based MMORPG the company were working on, Game Neverending, which goes some way to explaining how flickr has such a satisfying reward structure.