Agree, Coda (http://www.panic.com/coda) is one very slick application for web related work where lots of FTPing is required. It also supports syntax highliting for most popular scripting languages (Ruby, Python, Perl, PHP, JavaScript and others) and has a great CSS editor AND integrated Terminal.

Plus you can choose to preview how your web app looks like in various browsers from Coda.

There are many more features, it's one very useful and slick app for web development work - HTML/CSS and lightweight scripting.

For heavier jobs (Lisp and non-web based Python programming) I use Aquamacs - definitely check it out.