Sean Crowley of Crowley Vintage is a total vintage menswear nerd, and has an incredible collection of rare, quality vintage pieces. There's a Ralph Lauren / Ivy Style focus. Movie stylists go to him to pick up vintage pieces. He's a big deal.
He's also a bit of a dick. you should call ahead to plan your appointment with him, you should put everything back exactly as you found it, and if you don't buy anything, he's going to think you're a dick, because, again, he's a dick. You'll pay more than full price for some pieces.
I'd sooner recommend Alfargo's Marketplace. The people are nicer, the prices are dramatically better, the clothes are still fantastic, and the people appreciate vintage clothing from a modern perspective. Crowley actually shops there sometimes, that's a whole long story.