A nice little gem in OS X Mountain Lion is its inclusion of a new font called Avenir. According to Wikipedia, Avenir is French for “future”.
I found out about it when I started using Day One (my review), since it uses Avenir by default if installed on Mountain Lion. To get a better taste for Avenir I have had Byword for Mac set to use Avenir for the past couple weeks, and I have found it to be a really enjoyable font.
Turns out Avenir will also be included within iOS 6, and will be front and center in the new Maps app. Day One for iOS will also use it by default on iOS 6, and I suggested to my friends at Byword to include it as an option for their iOS app.
In the past, I have always sought the timeless classic Helvetica Neue as my font of choice for writing. I think Avenir may actually be my new default. If you have OS X Mountain Lion, give it a whirl.