A few suggestions for sessions you might want to watch. By no means does this mean other sessions on Day 1 are not worth watching! These are just sessions I went to myself and found to be useful or heard good things about from others.
KYN01 Day One Keynote - Ray Ozzie, Amitabh Srivastava, Bob Muglia and David Thompson
PC47 Microsoft Expression Blend: Tips & Tricks
PC20 ASP.NET 4.0 Roadmap
TL16 The Future of C#
PC21 ASP.NET MVC: A New Framework for Building Web Applications
ES01 Developing and Deploying Your First Windows Azure Service
PingBack from http://mstechnews.info/2008/11/some-reflections-on-pdc-2008-must-watch-sessions-day-1/
I watched "The Future of C#" and thought it was a great look into the future of the language.