YAMC is an easy to use and attractive email program, that supports multiple mailboxes, email checking, HTML mail and also offers an address book, calendar and more. It also includes a search function, customizable folders and several import/export options as well as a unique feature that allows you to search Google for any highlighted word in the email body.
More info:
hxxp://www.borg-kindberg.ac.at/yamc/welcome.php