One thing I keep seeing in here is discussion of "lining up code" and indentation. I would like to point the following things out:

eight spaces will always be twice as long as four spaces in any font.

two tabs will always be twice as long as one tab in any font.

any identifier on one line will always be the same width on the next line...in any font!

sure, if your teammates are using monospace and you're not, it'll look different...but you should be standardizing on something--whatever it is--and if that's true then it'll look the same for everyone...in ANY font! For laughs you could also try keeping everyone on monospace and giving half of them widescreen monitors...see how that goes.

If you're doing anything that relies on lining up code based on the columnar position of those characters on the screen, and not the scope of the identifiers you're using, I pose that what you're doing is a hack. Identifiers should never be constrained to a certain number of characters at the cost of the quality of their names. Aside from that...you're not still drawing ASCII boxes with asterisks for comments in your code, are you?

So drawing all of this together, if you start each line at the same place, and consistent spacing is the same width, and the identifiers don't spontaneously change width on each line, then your code actually WILL line up! ...until something is different.

for example:

identifier.Method().Property.ToString(); identifier.Method().OtherGuy.ToString(); //how lined up and pretty! identifier.Method().Sumthing.YouGetThePoint;

identifier.Method().Property.ToString();

identifier.Method().OtherGuy.ToString(); //oh no! misaligned!

identifier.Method().Sumthing.YouGetThePoint; //...but who cares? they're different properties!

The one point I'll concede is that non-alphanumeric characters are typically not very wide; these include )(][}{,:|";',`! and . This however could be fixed in a font editor...simply by making them wider. It's not a problem inherent with non-monospace; there just hasn't been a lot of demand for it, and so it hasn't been done yet.

In summary, personal preference is fine, but I think there's little practical reason to prefer monospace over non-monospace. You like the look of it? Sure, do monospace. You want more stuff to fit on your screen? Go non-mono. But the way people treat non-monospace like heresy is a little overblown.