While I make heavy use of a password manager, I still choose to memorize my email password, and not store it in a password manager, precisely because it is is relied on so much, and can be used to reset the majority of the passwords stored in the manager anyway.
For very important passwords that are stored in a password manager, salting it with a memorized phrase is a good idea. That way, if someone gets access to my password manager, they still won't be able to access everything in there.
