Just watched it while working on some stuff tonight.  Good things seem to be happening although much of it is in CTP or Beta form right now.  I'll need to resurrect my VPC images to install and play when I have the time. What's baking that's cool?

IE 8 - the integrated Firebug like debugging is what's got me excited for now.
Silverlight 2.0 - Dino Esposito joked about how Silverlight 1.0 was a declarative way to produce an animated gif (unless you just want a video player).  Now that a real control library is being developed, people like me will be able to seriously think of ways to use it.  I don't stream video but I do write a lot of code :)
Expression 2.0 / WPF - Ditto on Silverlight 2.0, WPF needs controls - and not just the kind you have to pay $$$ for.  In my best Steve Balmer voice I'd say "controls! controls! controls!" The blank canvas thing is cool but limited when you need to build something on a real world timeline with real world resources.

I didn't see ASP.NET MVC stuff in the keynote under demonstration but it was mentioned. Via Hanselman, Preview 2 is released today.

John Lam seems to be writing a multi-part article on DLR + IronRuby - a cool way to experiment with Silverlight although now I'm officially in love with Python and may not have room for a while. 

I'm excited to see what happens but I'm skeptical to put too much effort into this stuff until it's properly released.  Since I'm no longer a trainer and the apps I write have to be installable on client machines, I have less flexibility and time to get full fledged into beta stuff. It will also be interesting to see who wins the Silverlight / Flash war (and a war it will be). Microsoft is building its installed base pretty fast and with a better developer toolkit I will be interested to see what Adobe does with Flash.

Lots more lurking to do - even though all the cool people are at MIX, so much is online and so many people are twittering (I now have a "Twit" folder in my reader), one can almost imagine themselves there.