Font Awesome icons because they are modern and clean and vector so they look great on high resolution screens. It also makes it very easy for plugin makers to use a wide range of icons since all the Font Awesome "font" is available to the system.
I'll consider another tease, but the next tease may just be the beta. Worked through some issues last week with the new minPHP. Couple more to figure out, like why the "Remember Me" option doesn't work.. some incompatibility with the minPHP bridge I'm sure.