Aviate is a popular launcher acquired by Yahoo earlier in its development, and through a short closed beta, it's become a very mature option for those looking for a polished overall Android experience.
The main gist of it is that Aviate builds collections of your apps based on different types of activities. You can, of course, tweak those collections manually as well, and Aviate can offer suggestions to fill in collections (though this is really just a form of advertising rather than intelligent suggestions). Aviate figures out where you are and what time of day it is, and serves up relevant collections in custom-built interfaces called Spaces so you can better handle those activities. For example, if you plug in your headphones, it offers you quick access to media controls and your favorite music apps. Hit the road, and you'll be offered shortcuts to navigation home and to the office. It's a great idea on paper, but let's see how it pans out.