I've used Windows for many years, using Dreamweaver as my editor as it had a file tree which is based on a project (via Local, FTP or SFTP).
I need a web development IDE with the following functionality:
syntax highlighting for PHP, HTML, CSS, JavaScript
file tree - Local, FTP, SFTP, Project-Based (e.g. via the methods of Local/FTP/SFTP) in other words, like Dreamweaver
can open multiple files (tabbed)
Additionally, I wouldn't mind features like debugging, class listings, etc, as long as I can hide them away.