How do I reset Apple's Mail, in Lion, to default settings?

The following directories should be empty:

• ~/Library/Mail
• ~/Library/Mail Downloads
• ~/Library/Application Support/Mail
• ~/Library/Caches/Mail
• ~/Library/Caches/com.apple.mail

The following files should be removed:

• ~/Library/Preferences/com.apple.mail.plist*
• ~/Library/Saved Application State/com.apple.mail.savedState

In addition to the folders mentioned by Patrix, I discovered that Apple Mail (at least the OS X 10.9 Mavericks version) is using another folder, at:

...../Library/Containers/com.apple.mail

After I had tried to do a clean restart of Mail by disabling (re-naming) all the folders that I thought that it was using (and having done a Force-Quit of the process "cfprefsd" in my username, to further reset caches), my Mail froze on trying to start up.

When I also disabled the folder in Library/Containers, the Mail application was able to start up.