Leo W. at Buffer - http://blog.bufferapp.com/author/leo
Ryan Carson at Treehouse - http://ryancarson.com/
Jason Fried & DHH - http://37signals.com/svn
Matt Mullenweg - http://ma.tt/
Patio11 - http://www.kalzumeus.com/
Leo W. at Buffer - http://blog.bufferapp.com/author/leo
Ryan Carson at Treehouse - http://ryancarson.com/
Jason Fried & DHH - http://37signals.com/svn
Matt Mullenweg - http://ma.tt/
Patio11 - http://www.kalzumeus.com/
Dalton Caldwell of App.net - http://daltoncaldwell.com/
Suhail Doshi of Mixpanel - http://sufficientlyadvanced.net/
Jack Groetzinger of SeatGeek - http://jackg.org/
Eric Koester of Zaarly - http://ekoester.com/
Craig Newmark - http://craigconnects.org/blog
Mark Cuban - http://blogmaverick.com
Tim O'Reilly - http://radar.oreilly.com/tim
Yeah, I'm pretty sure evidence to the contrary is stronger. A little googling tells me C-levels and founders of forbes 100 are often proflic bloggers. Novell, Cisco, Oracle, a lot of founders of big companies in India, and many here in the non-tech sector blog as well.
Insofar as commenting on HN and other similar sites is quite similar to blogging, there's a lot of others here too.
Also on some of the other folks listed in sibling comments, like Richard Branson, I'd be very surprised if he were the one posting on the Virgin "blog" under his name. Just as executives and politicians have speechwriters, they also have exec comm and marketing staff to write blog posts.
Collis Ta'eed of Envato — http://notes.envato.com/author/collis/, http://inside.envato.com
Dan Shipper - http://danshipper.com/