Font Awesome are alright, but the quality felt like a step backwards from Glyphicons.
We wound up going with Google's Material Design icon set[0][1]. Released under Creative Commons, and can either be self hosted or can utilise Google's CDN. Has a nice selection, and can be rendered via SVG, PNG, or an i tag e.g. <i class="material-icons">alarm</i>. Only requires a single reference to the font file to start utilising.
The only downside with Google's Material Design icon set is that it has compatibility issues with Internet Explorer 9 and older. For older IE support, instead of writing pretty HTML like:
<i class="material-icons">face</i>
You write nonsense like this:
<i class="material-icons"></i>
Eww. But since our project breaks in IE9 anyway, we could utilise their font library AND use the prettier style of HTML. So no big downside to us.
The fonts are easy to stylise and Google provides a few recommended CSS styles (e.g. md-dark, md-18, md-light, etc) on the developer page.
If you use css frameworks like Foundation or Bootstrap they come with their own set of font icons as well.