Notify 2 Pro metamorphoses into lightweight e-mail client

E-mail's a very important part of our everyday lives. Between the newsletters, the personal correspondence, the "hold on, did you get that thing I sent you" messages, and the spam, we're still stuck with it. Mac OS X has an app for that. It's called Mail, but it's a bit too feature-rich for some folks, especially compared to the minimalist Address Book and iCal apps. What if there were an e-mail client for OS X that stripped everything down to the basics and added a nice layer of polish on top?