Saw Powershell in action! Wow - that is pretty cool. Its like an object oriented bash. And it's easily extensible. It's also available for XP, hmm, could be useful.
There was a great session on secure programming ("How not to screw yourself") by Corneliu Tusnea. This guy's neural kinetics were way above normal. Speed of presentation and thought process awesome to behold. He showed us Samy's cross-site scripting hack against MySpace (since fixed) and a bunch of stuff to help protect against this and other attacks on your code.
There was one session explaining how Vista-Vista and Vista-Server 2008 file copies are super fast because they use the less chatty SMB 18.104.22.168 protocol and Vista supports MTU or greater than 64k, and how some of this was broken in Vista pre SP1. Vista SP1 is a lot faster than Vista.0.
Then there was the TechEd Party. That was actually great fun. It was set up like an old style carnival with a fireblower and girls on stilts, but with original and ancient arcade games around the outside. Galaga! Pac Man! Old pinball machines too. Woo! Oh yeah. Tables full of dohnuts. And frreee boooze. Oh My.