The best I have found for advanced javascript to be is "Secrets of the Javascript Ninja"[1] by John Resig and Bear Bibeault. Highly recommended. Currently I am reading "Javascript web applications"[2] by Alex MacCaw and it seems to be well written and to the point as well.

[1] http://www.manning.com/resig/ [2] http://shop.oreilly.com/product/0636920018421.do