Apple-green velvet? "That was definitely Tracey's influence," says management consultant Michael Silber (far left) about working with designer Tracey Garet on his New York City living room. Tracey started out by laying in fine antiques and then "making it nuttier," much to the delight of her client, who admits he would have played it straighter on his own. Their four-year collaboration—yes, on this room—included much debate but no overarching plan. "We didn't know where we were going," Michael explains. "We only knew what we were doing next."

Discover the secret to mixing old and new.