[elektronaut]

I tried it for about a week and went back to monospaced. It wasn't a very pleasant experience. Code and prose are very different things. Special characters are very significant when programming, and tend to run together and be hard to read with a proportional font. Double space indents are hard to follow, and alignment beyond indentation is hard to get right.

It might be workable if you're working exclusively with your own code using tabs for alignment, but that's a luxury not everyone has.