+1 for Aquamacs. I've used Emacs on/off for 15 years and I've grown to detest the need to "feather my nest" every time I move to a new seat. I want a usable default configuration, and Aquamacs works reasonably well for me in this regard.

Customizations: Capslock == Ctrl, Emacs menubar is hidden, one .emacs entry for ye olde 'newline-and-indent. That's it.