Growing up as the son of an IBM executive in upstate New York must have given classic American designer O'Brien, 46, a head for business. Following a stint as a creative director at Polo Ralph Lauren, he set up shop in 1992 in New York City's SoHo, where he combined his design atelier with his furniture shop, Aero. The shop quickly became a destination for design aficionados, and soon O'Brien was creating interiors for tastemakers like Giorgio Armani as well as luxury hotels like 60 Thompson. But it was his 2005 Vintage Modern line for Target that lent mass appeal to his name. These days, with tableware for Reed & Barton and lighting for Visual Comfort, there's little in the home market that this retro-modernist doesn't have a hand in. —Deirdre van Dyk