I guess it’s a big deal to me when I legally purchase software, because I just don’t do it very often. Piracy and other methods aside, most applications I use are actually open source or free. Free software is nearly as good or better than other software out there, for what I need generally. Coda though is a professional web designer solution that is totally worth paying for.
Coda basically gives you one simple interface for everything you would need as a web designer. Check their site, it has a nice design worth checking out purely for the visual effects, but it also explains its abilities better than I can. I basically love the ability to create a profile for a project/site, storing FTP and SSH passwords for easy access, then just focusing on the project, keeping everything combined and balanced in one window. You can have the remote server on side, ready to FTP files using the powerful Transmit engine and files ready to edit on the side side, using the likewise powerful SubethaEdit engine. You can visually edit CSS files and using Regex search for functions. If you want to really change things, you pop open an SSH window without having to login and you can just work.
Overall, I find it has a great interface thanks to Apple’s beautiful design and it enables you to work very quickly. Worth the money!!