Just a couple of thoughts...
Email-links
If the email module is active, and you have an email-account working, Why have a ordinary mailto-link at Contacts? You should be able to use the email module to create new emails by clicking the email-adress of a contact or in a document.
Attachments
If an email has attachment you should have the abilty to load them directly to documents.
Tasks
You should be able to create a task with an email with the text inside. This would be very nifty for the workflow. I know someone already asked for this, but I think it is important.