Using a proportional font will break if you try to align code other than using indentation, e.g. aligning assignments.<p>More examples: <a href="http://mysite.verizon.net/astronaut/vim/align.html#Examples" rel="nofollow">http://mysite.verizon.net/astronaut/vim/align.html#Examples</a><p>Of course, I really hope nobody's coding like that. I've never seen anyone who's been able to maintain that kind of formatting consistently.<p>I don't see any reason why proportional fonts shouldn't work for most programming styles. The problem is that most existing proportional fonts aren't very well suited for programming. At the very least, you need a font with unambiguous shapes for similar glyphs, like 1lI0oO`',.;: