Depending on the concrete programming language you're using, you might be more interested in their WebStorm, RubyMine, or PhpStorm apps. JetBrains offers a whole range of development tools. Along with its built-in web inspector and CSS tools, it's a perfect choice for web professionals. It aims to be your FTP client, your version control tool, and MySQL database editor.
Panic's Coda is definitely one of the most full-featured development tools on the Mac. Though tempting at first, you don't have to automatically go for the 'more is better' approach: Some people enjoy having a single tool for (almost) all of their development jobs, while others prefer to have many specialized, focused tools. Some applications provide much more than just text-editing capabilities.
