I’ve redesigned this space after reading the excellent Practical typography by Matthew Butterick. I picked Charter as the font for the body text. Charter is recommended in the appendix of the aforementioned book as one the bests free-fonts by far. I tried Vollkorn from Google web fonts for a while before switching to Charter. While Vollkorn looked fine to me, Charter looks even better it feels crisper.
I picked fonts from the Source Pro family by Adobe as my sans & mono-spaced fonts, but I may switch to one of the DejaVu’s fonts if I find one that I like better.