Aquamacs is the Emacs editor that Mac users love. Aquamacs lets you write text from LaTeX manuscripts to to-do lists, from C to Cobol, Java, Python, Shell-script, Lisp, everything! Aquamacs looks and behaves like other Mac programs - even though it's still the powerful GNU Emacs with all the extensibility that millions have come to appreciate.
Emacs is a text editor of legendary power and configurability, but it also has a complex user interface that is very, very different from the familiar Mac way of doing things. Aquamacs tames the Emacs tiger: you get standard Apple shortcuts (in addition to the Emacs ones), nice fonts, tabs or one file per window, international input methods, Apple Help manuals and more. Aquamacs comes with a range of modes for various markup and programming languages: HTML, C/C++, Java, Python, Perl, AppleScript, Tcl, XML, R (S)... These modes have extra functions for the languages, including excellent syntax highlighting. You can even use Aquamacs to read news and e-mail, just like any Emacs.
Note: While the software is classified as free, it is actually donationware. Please consider making a donation to help support development.