Dan Kelley has been using TextMate for about a year, and loves it. He wrote a bundle for "gri". Lately, he is trying to get FireFox/mozdev to let him edit textareas in TM. No luck, so far (2006-02-03). Really, the goal would be to get things working in Safari, since Safari feels more like a mac program (e.g. emacs-style keystrokes are understood well by Safari.)