The keynote videos from day 1 and day 2 of PDC 2009 are now available.
The day 1 keynote features Ray Ozzie, Bob Muglia, and many other people coming on to present. This is the keynote talk where AppFabric was first announced.
The day 2 keynote features Steven Sinofsky and Scott Guthrie. If you're interested in Silverlight you'll particular want to watch this session.
I highly recommend watching both. The amount of planning and preparation that goes into producing these keynote talks is immense. There's a lot of material packed in on a very tight script and schedule.