(Her actually.) It's M+ 1mn Light (M+ fonts, Type 1, monospace). I think the whole family is attractive & readable and for programming on OS X I wanted something with a lighter font weight (it's got 5) to compensate for OS X's overly heavy rendering of light text on dark backgrounds. For Linux/BSD terms I tend to use either the medium weight or use monofur.
Samples: http://mplus-fonts.sourceforge.jp/mplus-outline-fonts/design... Design: http://mplus-fonts.sourceforge.jp/mplus-outline-fonts/index-... Bitmap font which I havent used: http://mplus-fonts.sourceforge.jp/mplus-bitmap-fonts/design/...