I'm very fond of Eben Sorkin's Merriweather & Merriweather Sans. The large x height make it a really nice and legible screen font.<p>Steve Matteson's Open Sans is another one that's become a bit of a go-to typeface for me.<p>Some others that I like <a href="https://pinboard.in/u:adrianh/t:font+free+good" rel="nofollow">https://pinboard.in/u:adrianh/t:font+free+good</a>