The best monospace font for programmers is M+.
Retina screens make subtle strokes and thinner weights look better, and M+ does that: its thin is ethereal, almost a stick font. I only use retina screens: at lower resolutions, bitmap fonts like Terminus can shine.
It covers Basic Latin, Latin-1 Supplement, Latin Extended-A, Kanji and Kana: beyond that, only a few monospace fonts like DejaVu have coverage.
0 is slashed to differentiated it from
1 is easy to tell apart from
Give it a shot? M+ is totally free and open source, and
installable on Debian & Ubuntu as
fonts-mplus. You can download the font from its
SourceForge page, but it's Xz-compressed.
So, here's a .zip file version of M+ you can download in one click.