No I havent visited the schools. Its just that UNC's research in Computer Graphics fascinates me a lot, but if I go to Duke, I'll probably be working in Theory or Computer Vision, both of which I am also very good at, but I dont like as much as Graphics. Plus, Duke is where one of my profs got his PhD from, and his advisor is calling me there, and he's really, really good in his field. Also, Duke offered a really good financial package.
Bottom Line: I dont know if Im willing to risk having a lesser passion for my research for extra money and so-called 'prestige', since everyone seems to know Duke, but arent sure about UNC (even though I am). And most of my faculty members and family want me to pick Duke, even though I keep telling them that UNC is the best in Computer Graphics.