Holly Madison and Hugh Hefner, Girls Next Door

Although Madison shared the Playboy Mansion with her costars Kendra Wilkinson and Bridget Marquardt, she was always Hef's No. 1 girlfriend. "I had planned to spend the rest of my life with Holly," he said in October 2008, adding that the persistent strain was her desire to have children. Despite the breakup, Madison continued filming the sixth season of the show -- which first aired on E! in 2005 -- and said "it's going to be even better."