I think the point Jason, and others in this thread, are making is that great investors understand that how a founder dresses (especially in tech) is a poor indicator for success. Their pitch and, as YCombinator has pointed out, the intelligence and drive are much better predictors of success. This is on top of the fact that investors aren't looking for the status quo, they are looking for visionaries who are going to make next great thing. Dressing nicely because everyone else is, shows that you are buying into the status quo, not changing it.