The duffle coat. There's no doubt of its classic status but there's also no doubt that there's still something of the naughty schoolboy about the classic navy woollen version.
So what do you do about that? On one hand you could visit a therapist and try to get them to help you rid yourself of all your negative connotations, allowing you to go to work wearing a duffle without worrying about being called into the headmaster's office.
Or you could get a coat like this Lavenham version. Whichever's easier. (C'H'C'M', $450)