This is hands down the best men's hat pattern out there. It's easy, free, and uses a single skein of yarn. I've made four out of Noro Silk Garden and see the recipients wearing them all over town. Just finished one in Cascade's Eco Duo and it's delicious.
Does your guy need a thin hat to wear while he’s working out, riding a bike, motorcycle, etc.? The Work and Play Beanie uses a thin, sport weight yarn to give him the extra warmth without being too bulky or hot!