Some recommended settings for your ~/.vimrc because we all hate tabs (right?):

set sw=4
set ts=4
set sts=4
set expandtab
syntax on

To get emacs to stop inserting tab characters and insert spaces instead, use this in your ~/.emacs file:

(setq-default indent-tabs-mode nil)

You can turn off paragraph indentation (which is on by default) and increase the space between paragraphs to indicate where they begin and end:

\setlength{\parindent}{0.0in}
\setlength{\parskip}{0.1in}