Smultron: Used this a bit. not bad but I didn't really take to it. Missing a number of features
Vi: still use it regularly, but I don't have much skill with it. Extra handy for quick editing of a single file (I use the command line a lot so vi is convenient)
Aquamacs/Emacs: Gave this a shot but really had no idea how to use it. Gave up in the end
Netbeans: Been using this for years and found it mostly the best fir for my needs. Looked around when Orace took it over and ended up with...
Rubymine: Excellent. Great fit for me, although I'm still on 3.1 as the newer releases run like molasses on my aging macbook. It's a bit heavyweight, but it has a ton of really useful features.
Kod: Showed great promise as a Scite replacement but seems to have been abandoned. (Scite was what I used in Windows for years. fantastic once you change the default fonts)
Texmate: Used the demo, couldn't see what it offered over netbeans
GEdit: Used this all the time in Linux and was surprised to find it runs fine out of the box on the Mac! Great for reading extra large files like long logs etc.
Textwrangler: For some reason I really can't get to liking this. I give it a shot again every now and then but it just doesn't seem to work the way I do
Coda: Looks lovely but I just couldn't get over the price.