OK, here is a nasty virus trick. The message gets sent in a password protected zip file. The text of the messages says here are my pics and enter in the passwd xxxx to view the archive.
The big problem is that normal avscanners cannot open the zip file to scan the contents since it is password protected.
However, the user can be easily socially engineered to open the file and blam. The text of the message is nice and enticing making it look like private email with dirty pictures accidentally sent to the user...
---Mike