What are the changes in the Unity 4 editor?

This is too big of a question to be answered in a paragraph or two, so I put together a video tutorial walking through all the changes in Unity 4:

http://fragileearthstudios.com/2012/11/10/changes-in-the-unity-4-editor/

If you see anything missing, add it below and I'll try to get it into the video.

Note: This video doesn't include an introduction to Mecanim. That topic is so large that it needs a separate video, and I'll post that to Answers when I finish it.