Personally I believe that emacs got it right, that tab widths should always be at 8, and editors should indent intelligently with spaces as needed. (Actually it's kind of a bummer that tab characters go into text files at all, ever. Just like the whole confusion over what is a line (cr, crnl, nl).)
M-x eval-expression Ret (setq tab-width 4) Ret in Emacs will set tabulation stops at 4 positions intervals. That's what many do.
David