Hey,
There's a font from Adobe called Source Code Pro.
Very suitable for programming and coding.
Even the zeros have a dot in the middle so a capital "O" definitely looks like an "O".
More info:
http://blogs.adobe.com/typblography/2012/09/source-code-pro.html
In the preview, font size is set to 20.
Download:
It's so good, you might want to include it in the Arduino ERW as the default font type.
You're welcome 
