My tips for interesting lectures from Microsoft MIX 2009 conference:

Advance Your Design with UX Design Patterns

boring lecture, equivalent to reading Infragistics Quince design patterns list, but at a slow pace - skipped most of it

Ten Ways to Ensure RIA Failure

my recommendation to project managers - great one, fast, all the good points

The Way of the Whiteboard - Persuading with Pictures

could be summarized in 10 minutes, but the last third is great (6 kinds of questions -> 6 kinds of diagrams to answer them) and the rest it at least infotainment

Escaping Flatland in Application Design - Rich User Experiences

good in the beginning, second half is boring WPF ad, and WPF is dead/killed by MS anyway - skipped it

File|New -> Company: Creating NerdDinner.com with Microsoft ASP.NET Model View Controller (MVC)

great introduction to ASP.NET MVC by ScottGu

Off topic: Design Principles for Windows 7

on todo list :)