I think it would be great to define a smiley per message, thus when you receive a message that has a smiley set in the X-tag, it would appear in the message list: there is already a "Subject", a "From" and a "Date" column, we could add a column for the smiley associated to the message if the sender chose one.

Also, enabling smileys inside messages would be great, like Opera does in its mail client.

The svn version has a built in html editor that you can enable. If your using the beta2 then you have to add the tinymce patch. Don't have a link sorry.