I like two hats.
One is the classic army "Visor Cap", which is not only extremely comfortable and of extremely high quality, but also protects the eyes from the scorching sun and looks very spiffy, not to mention the slight air of authority it gives a person. Plus, since I'm a reservist, I have a very nice pair of visor caps for parades that I must wear.
The second is the army fatigue cap. Very comfortable, stylish and simple, it's also nearly indestructible by normal means and I would happily wear one every day for the rest of my life.
Fedoras are stylish and awesome, but they're not as practical, so they're in third place. Top hats are good as well. Ushankas and fur hats are good for the winter, but still not that good for general use.