I really like a subtle feature of Tableau 5 that should greatly enhance the dashboard viewing experience.  

While navigating a date range may seem simple, it's not.  Dates are an example of how a single universal dimension needs to be sliced many different ways, depending on the context  and data set.  The simplicity of the dialogue in the example viz is what makes the dashboard powerful -- the viewer is presented categorized options for slicing in just a few clicks.

Good stuff.