It seems an attachment is either very good or very bad. That's why I've taught Windows Mail to highlight any message containing an attachment (the same works in Windows Live Mail and Outlook Express, too).
Highlight Messages with Attachments in Windows Live Mail, Windows Mail or Outlook Express
To highlight messages with attachments in Windows Live Mail, Windows Mail or Outlook Express:
- Select Tools | Message Rules | Mail... from the menu in Windows Live Mail, Windows Mail or Outlook Express.
- In Windows Live Mail, hold down the Alt key if you cannot see the menu bar.
- Click New… if the new rule dialog does not come up automatically.
- As the rule's condition, select Where the message has an attachment.
- Set the action to Highlight it with color.
- Select a color by clicking on color in the Rule Description.
- Give your rule a meaningful name ("Highlight Attachments", for example).
- Click OK.
- Click OK again.