I've been very busy with some, uh, scheduling issues this month. As you can imagine there is a lot that goes into making a big decision like this. I'm personally very excited about (a) reach for developers, and (b) getting the bits into the hands of customers sooner. I met with a lot of people at the last PDC and TechEd who love the idea of the ease of managed code being brought to the coolest new technology for Windows. But they really wanted reach. Wish granted.
As BradA mentions, a lot of our day to day stuff gets a little easier. The key thing for the CLR team is that Whidbey (v2.0) ships with Longhorn. That means the same version of the CLR/.NET Framework will power Yukon, Longhorn, and the now down level WinFX. And since Whidbey Beta 1 is already available for download, you can get a head start on this version of the engine if you haven't already.
Finally, there is a lot of great commentary on Jim Allchin's Channel 9 interview. Jim is one of my favorite senior executives I work with. He's very smart, and deep down he's still a developer (you'll recall the demo he wrote on stage at the PDC was done in his favorite editor, vi).
Stay tuned for more WinFX info. I expect things will get very exciting...