In fact, a couple of them aren't really Silicon Valley based, and spend most of their time in New York, such as Twitter co-founder Jack Dorsey (above) and Pete Cashmore, founder of Mashable. And there's several on the list that you've probably never heard about — the result of desperate Googling in researching this topic.
Marc Andreessen is listed as well dressed even though he wears the standard VC uniform of Sand Hill Road: blue sports coat and tan trousers. Vanity Fair says he's not afraid to put on a power suit when needed.
Dressing well is better appreciated in New York than in Silicon Valley where the business park culture of the tech companies favors the style set by Mark Zuckerberg's always-on hoodie plus T-shirt and jeans (above at Crunchie Awards). San Francisco's tech workers dress a little bit better but they try not to.