Though not really mentioned in the keynote there are a lot of sessions on VSTS 2010 at the PDC; it is going to be a major really major release.
Chatting in between the sessions with other delegates there seems to loads of interest in the new testing features, but we know this is pain point from Alt.net meetings. It will be interesting to see how these new tools deliver, I am sure the manual testing tools will be useful, but I am a bit more doubtful over the UI testing tools. We have all seen the demo promise of these products before and hit problems when we try to use them for real.
I think the improved integration for Office is also going to be important. At the moment we use the eScrum template for VSTS and the main reasons for this are the easy project visibility it gives to non-developer users via it’s web site and the way it manages the relationship between the product backlog and sprint tasks (given the lack of hieratical work items in the current VSTS). With 2010 I am not sure we are going to need the eScrum web site. The ease of reporting (and live work item updating) in Excel and hieratical work items will make this it superfluous, so the basic Agile template in 2010 may will be able to do the job.