Sunglasses are cool. With the right pair, you can miss 14 fairways and still look every bit the "player." I've been wearing them for about three seasons, and it's catching on. Even Justin Rose—about as traditional as you can get—plays with shades. They seem to match the athletic-driven style of today's clothing, and there's a big benefit to shielding your irises from six hours of direct sunlight.
My advice: Save your Wayfarers for non-golf days. Go with a modern frame style that's both lightweight and wide enough to provide full protection. I wear several models from Oakley, mostly the Flak Jacket [left]. When trying on a pair, make sure the bottom edge of the frame or lens doesn't cut off your view of the ball when you look down at address. And ask if the lenses are polarized. Some lenses are so good they can actually increase depth perception, making it easier to read greens.
Oh, and never rest your shades on the bill of your cap when you take them off. Wrap them around the back instead. That's the Tour way. It looks cool, and it avoids covering your cap's logo—critical for keeping sponsors happy.