HatCenter - Site devoted to hat wearers and designers. Resource of manufacturers, catalogs, shows, shops, history and more. Not an online store.
Hats-Online - All styles and sizes of men's hats.
Mike the Hatter -
rallycaps - Over 800 logo sports hats including hard to find teams.
Stark & Legum - Hats for all seasons and weather.
Worth & Worth - Hard to find styles and hard to find hats.
The Hat Box - Novelty and specialty hats in a variety of styles. Return or exchange within 30 days.