Unless I'm missing them in the summary, I'm surprised by the lack of NOLA listings here. I only travel there once in awhile, but George Bass is one of the most beautiful menswear shops I've ever seen. It's a small shop of impeccable quality. They're incredibly friendly, informative and generous with conversation and restaurant recommendations.
And Rubensteins's is the definition of a classic American menswear store. Have an Abita while you shop.
While not a full menswear shop, even if you don't wear hats, if you don't at least pay a visit to Meyer the Hatter for the conversation, you're missing out on one of the true old-school New Orleans institutions.
The great thing is that these three very different stores are within a block of each other.