I've tried lots of themes, but I keep going back to Bozhidar Batsov's Zenburn[1], which ships as the default theme with the same author's Emacs Prelude[2].<p>[1] <a href="http://emacsthemes.caisah.info/zenburn-theme/" rel="nofollow">http://emacsthemes.caisah.info/zenburn-theme/</a><p>[&] <a href="https://github.com/bbatsov/zenburn-emacs" rel="nofollow">https://github.com/bbatsov/zenburn-emacs</a><p>[2] <a href="https://github.com/bbatsov/prelude" rel="nofollow">https://github.com/bbatsov/prelude</a>