Sophia Bush has vowed to remain single two years after splitting from boyfriend Chad Michael Murray, because she's holding out for Mr. Right. The TV beauty insists it'll take the perfect man with ambition, a sense of humour and an environmentally-friendly outlook to make her commit again. The 25-year-old says, "He's got to make me belly-laugh. I do ridiculous things to make myself laugh all the time. "(I'm looking for a) driven, motivated and smart guy. Intellect is the sexiest thing in the world to me. You've still got to make me laugh." And Bush insists her dream man has to be environmentally-aware. She adds, "I can't imagine dating someone who wasn't, because I would be up in his face about it all the time."