Postbox address avatars
How nice, avatars! As you type in the To field, the photo of your contact is next to their email address.
Here’s how this works, I think: I’ve signed in to Facebook via Postbox, so they grab the profile photo from there. In the case that your fiancé isn’t on Facebook ;) they grab the photo from your address book. Very nice.
I’ve been using Postbox for the past few months and there are plenty of juicy UI tidbits throughout. Definitely worth taking a look!