The Aptana Studio Community Edition Is A Free, Open-Source, Cross-Platform, Full-Featured Web Development Environment

Aptana Studio 1.0 (formerly Aptana IDE)

The Aptana Studio 1.0 (formerly Aptana IDE) is a free, open-source, cross-platform, JavaScript-focused development environment for building Ajax applications. It features code assist on JavaScript, HTML, and CSS languages, FTP/SFTP support and a JavaScript debugger to troubleshoot your code. Get the Community Edition now!

They also offer for purchase an Aptana Studio Professional Edition adds new features for the professional web developer on top of the original features of Aptana Studio Community Edition. Compare features between the free and paid editions to find the set that best meets your needs.