Wow! I've had so many programmers react with shock when I tell them I use proportional fonts, that sometimes I think I'm the only one. I'm glad to hear your comments and the others here.

I really enjoy reading text in proportional fonts much more than monospaced. That's true for program code as much as any other text.

Like you, it doesn't bother me to lose vertical alignment. The only vertical alignment that matters to me in code is the indentation, and that works fine in proportional fonts. (The one exception being that the popular two-space indents are really lousy in a proportional font. So I prefer tabs, or if spaces are a requirement, four-space indents.)

In fact, some time before I started using proportional fonts, I'd already changed my coding style to avoid vertical alignment other than the left margin. I used to write code something like this:

  function someFunction(aParam,                   // This is the the main thing
                        anotherParam,             // This is another thing
                        aParamWithALongerName) {  // Remind me what this is for
      firstStep();        // Here is a description
      secondStep();       // of these three statements
      thirdStepSortOf();  // that go together
  }

That kind of code is the very reason for coding in monospaced fonts, but why? It is a pain to maintain and keep the spacing right, and in this (fairly realistic) example I find it extremely unhelpful to have all that whitespace separating "aParam" with its comment.

Instead, about ten years ago, I switched to a style more like this:

  function someFunction(
      aParam,  // This is the the main thing
      anotherParam,  // This is another thing
      aParamWithALongerName  // Remind me what this is for
  ) {
      // Here is a description of these three
      // statements that go together
      firstStep();
      secondStep();
      thirdStepSortOf();
  }

Now it may not be as "pretty" to have those comments on the parameters not all lined up as they were before, but it's a heck of a lot easier to maintain, and to my eyes it's easier to read too. The comments about the parameters are not related to each other, they are related to the parameter that each one applies to. With this style I can read:

      aParam,  // This is the the main thing

as pretty much a single unit, where the excessive whitespace in my previous style made it hard to match up each parameter with its comment.

Having made this change, some time later I discovered that the version of Visual Studio I was using at the time supported proportional fonts, gave it a whirl, and like you, found I really liked it.

It is true that when I read other people's code who've used columnar alignment, the alignment doesn't work any more. But for the most part that just doesn't bother me. In the few cases where the alignment really makes a difference, I just switch to a monospaced font to read that file.

My favorite editor, Komodo IDE (or the free Komodo Edit), does a marvelous job of handling this. Like many editors, you can set up a customized theme of fonts and colors, but unlike any other editor I know of, each theme includes separate selections for a proportional font and a monospaced font. For some reason they don't provide a keyboard shortcut by default to switch between them, but I mapped Alt+O (on Windows) which is unused otherwise. I remember it by thinking "prOpOrtiOnal" and "mOnOspaced". :-) So I can switch between my favorite proportional and monospaced fonts easily, and it also remembers that setting for each file I've edited.

UltraEdit and UEStudio (Windows only) are not bad here either. They don't have an explicit way to select proportional vs. monospaced, but if you press Alt+C to go into column selection mode it switches to a monospaced font while in that mode. So that's a way to view a monospaced file. I wish more editors had this kind of flexibility.