Every guy should have a good hat. Think about it...
1. If you have a bad hair day you can still look stylish with a hat.
2. If you are losing your hair you can cover it up with a hat.
3. You will get noticed because most people don't wear them often.
4. Hats protect your head from the sun
5. Some hats keep your head nice and toasty
Now, I should clarify and say that I'm not talking about baseball caps. Though they are functional and appropriate for athletic activity, sporting events, gardening, etc., they aren't "stylish" at the moment. Here are some examples...
You can find hats like these at any department store, Urban Outfitters or GAP. My husband has a hard time finding hats that fit well, so if you are in the same boat, try knit hats as shown in the last photo.