I'm also a big fan of Growl, a system-wide notification system. Growl comes with a neat little plugin called "GrowlMail" that will pop up a little alert whenever you get a new message. It'll show the title, a brief teaser, and perhaps a bit more. It's also very configurable and useful for much much more.
I've found a few:
Mail Unread Menu
Mail Unread Status Bar
I'm also a big fan of Growl, a system-wide notification system. Growl comes with a neat little plugin called "GrowlMail" that will pop up a little alert whenever you get a new message. It'll show the title, a brief teaser, and perhaps a bit more. It's also very configurable and useful for much much more.
Dave
The address for Mail Unread Menu download is http://www.apple.com/downloads/macosx/email_chat/mailunreadmenu.html
I've used this program for a while now and it works great!