Personally, Proggy is the only font that I can agree with @ spoondan's complaints about. But I wouldn't use it for other reasons. Too narrow for my liking. However, I have to flat out disagree with his assessment of ProFont and Droid Sans Mono having confusing O and 0's. The slash through the middle really drives the point that it's a 0..
Thanks for taking the time to put that together. Please note, however, that I complained about Profont's lowercase L looking like a one, not about its zero. Also, the original article's rendering of Droid Sans Mono does not have a slashed zero. Is the original article in error or did you perhaps accidentally reuse Profont for the Droid Sans Mono sample?
It's possible that you just have sharper eyes than I do; I have been getting older (a deadly habit I keep meaning to break, but the withdrawals seem prohibitive). However, just to clarify, my point is not that these glyphs are indistinguishable when directly compared, but that they can mislead you while reading code. I can certainly tell them apart when I compare them. But can I immediately see that "e1" is "e-one", or that "42l" is the long integer 42? If not, having wasted hours on such stupid things, I would disqualify the font.
Personally, Proggy is the only font that I can agree with @ spoondan's complaints about. But I wouldn't use it for other reasons. Too narrow for my liking. However, I have to flat out disagree with his assessment of ProFont and Droid Sans Mono having confusing O and 0's. The slash through the middle really drives the point that it's a 0..