So how does SQL Server pick which plan to run?  If you've ever wanted to get a better understanding of how the Query Optimizer works, this is the talk to attend.  Come listen to a member of the Query Processor development team explain how a query goes from SQL to the final plan.  This talk will cover conceptual topics like how query trees are built and how the optimizer stores all of the alternatives it is considering.  Additionally, the talk will examine examples in areas including index matching, parallel query generation, and update processing so that you can apply these concepts to better debug your own queries using the same techniques.