Yeah, we cant forget whitespace (indenting, space alignment, etc).

In a 100 char wide code line, how many actual non-whitespace chars would there be on average?

I was wondering the same thing, yes. I'm often an annoying stickler about keeping line length for text on the web set to what a couple centuries of book design have taught us makes long-form prose more readable, but code is not prose. I try to keep multi-line comments wrapped to around 78 characters, but I'm not really too worried about code.

(This invites a rant about people, usually people who use Emacs, who put hard line breaks in text paragraphs, but I'll save it for another time.)