Congrats to Robert Scoble on his new gig, and no disrespect intended to great MS bloggers like Dare Obasanjo and Niall Kennedy, but for my blogging dollar, the best blog ever published by a Microsoftie is Jensen Harris' Office UI blog. I'm not the first to note it, but I wanted to chime in with my vote there. Honorable mention goes to Ray Ozzie, who's infrequent, but then some of the very best bloggers are.
It helps that Jensen's working on Office 2007. (If they paid me, I might call it The 2007 Microsoft Office System, but they don't. Speaking of branding nazis, there's only one "e" in "Movable".) Office 2007 is the single most impressive and ballsy effort that Microsoft's put into anything since Word 6, which I think was the best desktop software application ever created.
I'll hopefully expand on these thoughts more when I've got a few minutes, but I wanted to throw that out there while I'm thinking of it. Commence flames... now!
(More evidence of Jensen's greatness: The phrase "Install the Send a Smile tool" appears in a post. Really, shouldn't we all install the "Send a Smile tool"?)