Wanted to give a shout out to the Textastic Editor for the Mac. Textastic is a nice lightweight text editor which I use for quick edits of HTML, Markdown and other code. It started out a very basic editor and has steadily improved with nice features including great syntax highlighting. The latest addition is support for Emmet, a tool for quickly creating HTML and CSS code with tab shortcuts.
If you own a Mac, definitely worth a look. It is $8.99 on the Mac app store.