I'm in limbo at the moment in a Text Editor of choice. I've been using BBEdit for a pretty long time and was pretty happy with it. But then I hit a bug in version 8 that's only going to be fixed in a future point release of the current 8.5 version (really a 9.0). Unfortunately for me, version 8.5 has also removed a feature that I came to rely on, so there is no point me upgrading.
TextMate is meant to be the new cooler, hipper Mac Text Editor King. So I had a good look at that, but it seemed I was going to spend more time trying to get it doing what I wanted (or what I thought it should do) rather than actually using it productively.
Smultron is really good and completely free, but I was having similar issues as I was with TextMate. It seems I want a combination of the two. The developer kindly pointed me in the right direction in the source code, but there is no chance of me getting my head around that.
At the moment, since to stand any chance of posting anything on this site I have to post via ssh from Work (ssh! don't tell them), I've resorted to using Vim. It maybe that Vim does everything I want anyway.