I'm prototyping the user experience for a web app project, iterating with users twice a week. I've been testing different approaches (modals vs new pages, edit buttons vs hover effects, etc) by putting users in the driver's seat, observing their reactions and gathering their feedback. So far, I've been using jQuery, Backbone.js and Express to test different workflows and UI elements, as well as provide a simple data persistence layer. In my quest to rapidly prototype a solution against real world extractions, however, my gut tells me there ought to be a better way.
For those that have a spare moment, I'd love to hear how others in the HN community approach the same goals. Specifically, what tools and processes have you found to be effective in prototyping a quality user experience?