Sparrow
For Mac and iPhone users who have been looking for a great Mail alternative, check out Sparrow. This is an elegant, simple, straightforward email program that I have been using concurrently to Mail for a while now and love dearly. Version 1.3 for the iPhone now adds POP email support (originally it was IMAP only and at first was just a Gmail client but has evolved since) which, from that perspective, brings it to parity with the Mac version. The site's iPhone page has a cute "emulator" that shows you what happens when you apply specific clicks or swipes to the app. If you integrate it with your FaceBook account it will pick up your friend's profile pictures into your mail messages. Definitely worth the detour.