How to force Mail.app to show messages in plain text
If you read a lot of emails from exchange users this is a must have. It fixes the super small fonts that exchange seems to like to send by default. Simply run this in a terminal:
defaults write com.apple.mail PreferPlainText -bool TRUE
I’m not sure why apple made fixed width fonts a preference pane option and decided to leave plain text out. Having both seems seems important to me.