Text Editor Actions (TEA) for Coda (formerly Textmate Emulation Applescripts) are some of the text manipulations that I think ever editor should have, implemented as a Coda plugin. I originally began work on TEA because I was interested in Coda's all-in-one workflow but completely uninterested in abandoning Textmate's excellent HTML editing capabilities.
For more information, including documentation and downloads, please see the TEA for Coda site:
If you want to try the latest development version of Coda, you can download and build the plugin from source like so:
git clone git://github.com/onecrayon/tea-for-coda.git cd tea-for-coda python setup.py py2app
If you wish to create a development version, you can run this instead:
python setup.py py2app -A
This will create a normal version of the TEA plugin, but symlink all the internal files so that you don't have to rebuild the plugin to try out changes (you'll still need to relaunch Coda between changes, though).