For some reason I keep comments no longer than 80 chars long to be sure that they can be read without horizontal scrolling. I''m wondering how many chars/line coders view in their IDE. I thought that it is time to take a definite decision in this issue.

I think 77 was the safe length from along time ago. Usually because of the old character windows (80 wide) IDEs.

that way it gives space for borders and so on.

BC2 (aka turbo c2) had it set to 77, and I think borland c++ 5 (not builder) had it set to 77 aswell.
I know that if I use ms-edit or pc-edit (os2) and in binary, I used edit.exe /77 filename.txt so it would fit.

oh wait, I think Borland C++ 5 had the actual end of page marked as 80. I forgot about it. That was for the old 80x25 and 80x50 screens