Javascript, DHTML, Drag-and-Drop

I've been doing lots of javascript and DHTML stuff lately. I'm working on a project that is really neat ... it's an query builder that allows the user to build a query using drag-and-drop.

While searching for help with javascript and related subjects I've come across several extremely useful javascript libraries, examples:

   
• Sarissa (cross browser XML library)

   
• Javascript drag-and-drop library (Based on a lib by Youngpup)

   
• And an adaptation of that library