What are the best tools do you use(paid ones as well as free) to develop a webapplication? I am looking for RAD(rapid application development) tools which increases productivity like IDE, decent debugger, drag and drop for web UI. Any added functionalities to check for security like SQL injection etc., will be added bonus points. I am particularly interested in web applications using open scripting languages(ruby, python and PHP) with some kind of MVC framework(likes Ruby on Rails, DJango or CakePHP). It should work on platforms other than windows.
Note: I am not looking for developing website on any CMS tools.
Thanks
-- PK