While you can set your own font in your terminal or other tools, it will not change the default "Monospace" font that some applications use.
To change that, edit 
  ~/.fonts.conf
  
    Show archive.org snapshot
  
 and add settings for the "monospace" family. Here is how it looks on my machine now:
<fontconfig>
  <match target="pattern">
    <test qual="any" name="family">
      <string>monospace</string>
    </test>
    <edit name="family" mode="assign">
      <string>DejaVu Sans Mono</string>
    </edit>
  </match>
</fontconfig>
Fill in "DejaVu Sans Mono" with your preferred font's name.
Posted by Arne Hartherz to makandra dev (2012-11-13 16:57)