CodeProject: Font Survey: 41 of the Best Monospaced Programming Fonts. Free source code and programming help.
There are a lot of different fonts that are good for programming. Some features that make one font better than another include general readability, of course, but also whether different characters are distinguishable. For example, do “l” and “1” and “I” look the same or different? How about “0” and “O”?