What is your favorite Javascript UI framework out there ?
richcollins: You don't have to write any of your backend in Javascript w/ SproutCore or Cappuccino.My favorite by far is Cappuccino.  It designed almost exactly like Cocoa, which is a fantastic framework for writing apps with UIs.  It comes with a ton of components that are already designed for you.  You can completely skip the cost of a graphic designer (you still have understand interaction design).