Some names that spring to mind, off the top of my head and in no particular order: Loren Brichter, Marco Arment, Matt Gemmel, Matt Gallagher, and Steven Frank.
Hewitt has doing some punditry himself lately. Interesting reads, he seems to believe that the open web doesn't have enough direction and will fall to apps unless somebody takes the reigns.
He developed much of Firebug and worked at Facebook in the mobile division (creating the Facebook iPhone app), for those who don't know him.