I've yet to find a font that I like more than DejaVu Sans Mono. It strikes the perfect balance between being monospaced and looking good IMO. Plus it's open source easily installable everywhere.
I've tried almost every other "programmer" font but there's always something that rubs me the wrong way. In the case of M+, it just looks thin and silly.
I looked it up in gedit, and it turns out Dejavu sans mono and Ubuntu mono are practically identical. Really minute details. I prefer Ubuntu because it's less fuzzy on my non-retina screen, though. For fun, try Tex Gyre Chorus Medium and show it to a programmer and say it's your favorite programming font.
Yeah, DejaVu Sans Mono is perfect, though sometimes I also use the new Source Code Pro and the old ProggyCleanTT (like when I'm working for several hours and my eyes need something more sharp).
I've tried almost every other "programmer" font but there's always something that rubs me the wrong way. In the case of M+, it just looks thin and silly.