MDaemon 7.0 - Faster Passwords, Rich Filters

With some extra threads devoted to local mail delivery and the user interface, MDaemon 7.0 promises to be more responsive. The latest SpamAssassin installation (including the ability for automatic updates) provides spam filtering, and you can now make MDaemon enforce better passwords. The web-based interface also gets an -- Internet Explorer-only -- rich HTML editor.
MDaemon is a solid and well-rounded mail server that you can trust. (Windows)