The main emacs website is <a href="http://www.gnu.org/software/emacs/"> here </a> <br><br>

Aquamacs works very well for Mac users: <a href="http://aquamacs.org/"> Aquamacs </a><br><br>

I use emacs because I can seamlessly go between Latex, R, C, Python,
and other programs using a single editor. It takes a little bit of time to get used to emacs, but the advantages are huge. See some of my emacs tips <a href="emacshints"> here </a>.