Day 1 was unbelievable!!! Packed with announcements, partnerships and code.. code.. code.  This is a truly great experience, without question the BUZZ from day 1 is centering around three hot topics:

1. Silverlight 2 Beta 1 and the fact that this is being used TODAY by Aston Martin and Hard Rock cafe. (http://memorabilia.hardrock.com/)
2. IE 8 and the features baked into it CSS2.1, HTML 5 and WebSlices
3. Deep Zoom(Seadragon) technology built into Silverlight 2 (wow).

Chris Koenig & Scott Hanselman give a nice overview of these topics: 

• Silverlight 2 and IE 8
  http://blogs.msdn.com/chkoenig/archive/2008/03/06/mix-08-keynote-announcements.aspx
• Deep Zoom(Seadragon)
  http://www.hanselman.com/blog/DeepZoomSeadragonSilverlight2MultiScaleImagesAtMix.aspx
• First look at IE8 Activities and WebSlices
  http://visitmix.com/blogs/Joshua/IE8-Activities-With-Jane-Kim/

I highly recommend checking these blogs above as well as www.VisitMix.com.  For all the latest and greatest of MIX08.