STANISHJOHND  Why no 10.4 (Tiger) version? Not all of us have the hardware to upgrade to Leopard.  
(Version 20090104)

ALBION  Yes, it is the best Emacs on OS X, because it's more of an Emacs than Aquamacs, the only credible competitor.

It is actually not a "port" at this point. Emacs built from source is almost exactly the same thing as Carbon Emacs. I think Carbon Emacs still bundles some elisp that isn't part of the standard distribution. Otherwise, the differences are mostly cosmetic. I wouldn't swear to his, but I seem to remember reading that the current Mac codebase, called nextstep in the cvs tree, actually uses Cocoa interfaces, not Carbon. No doubt someone else here can shed some light on that subject.

Anyway, this is the OS X Emacs of choice.  
(Version 20090104)

STATSMAN  I've been using Carbon Emacs since March 2006 and to me this is by far the best emacs port to OS X. Updates are frequent and current. Kudos to the developer!!  
(Version 20080405)

ZZAMBONI  This is my preferred Mac port of Emacs: it is frequently updated, comes with many packages, and stays true to the original Emacs.  
(Version 20080405)

NADEEMF  The latest version fixes the problem I had where numeric-keypad actions looked just like typing on the main part of the keyboard.

Shame that the lisp load-path doesn't include anywhere not contained within the application package (so that you can store your extra lisp libraries in a safe place which isn't replaced when you upgrade the application). Also strange that '/Applications/Emacs.app/Contents/Resources/share/emacs/site-lisp' isn't in the path.  
(Version 20060901)

LEE-MAN DUNCAN  I just downloaded Carbon Emacs 20051101 on my OS X 10.4.3 box, and I have a problem.

Emacs seems to start up Finder each and every time I start it, even if I run it with "-q" (the "do not load an init file" option).

I do not use Finder: I use PathFinder instead.

So if I try to use Emacs, I get two "finder"s running! This might be enough to drive me to VIM (argh!).

Otherwise, what can you say about emacs. At least this version uses the Apple key as a Meta key -- I hate Emaxen that require using the Escape key.  
(Version 20051101)

ANONYMOUS  How about getting rid of the ugly gnome icons when you build a mac application?  
(Version 09/2005)

SCHMELDING  That's a screenshot? Funny. How 'bout a screenie of the app in action?  
(Version 09/2005)

NADEEMF  The best implementation of single-window emacs in active development that I have found.

Many distributions of emacs for OSX have fallen by the wayside and haven't been updated to work with system upgrades, but this is being actively developed.

Unlike Aquamacs it holds all files/buffers in a single window, a 'limitation' that I actually require.  
(Version 08/2005)