This is mostly covered... When logged in as user with email not validated, a block called 'Email Validation Nag' appears on the right sidebar that looks like:
Confirm your email address
To access the full functionality of this site: Please click the link in the email sent to the address you registered with to validate your email address. Check your spam folder if you think you have not yet received the email.
I think this should be top of the content area of the page, bold, punchier and perhaps red or another color. It should be very prominent, especially if you're planning to set these unvalidated users to have their accounts deleted after a one....
I propose putting it in the top of the content area and changing to:
Important: Please confirm email address
You will not be able to access all features until you have validated your email address. Please look in your email for a message from this site and click the link within (check your spam, too). Note your account will be deleted after a week so please do this now''
Or similar... Ed?