GNU Emacs is an extensible, customizable, self-documenting text editor, which can be extended with Lisp code
TextMate is a text editor for Mac OS X.
"I feel like emacs is so much better than textmate"
from question "Completely lucid tabs and spaces in emacs?"
"Textmate is a better emacs for macs though that won t help you with solaris"
from question "Is it worth investing time in learning to use Emacs?"