I would say, go to Cornell... you already know people in Michigan, so going to Cornell will increase your social circle with the professors. This will help you when you go to industry/academia as you will have lots of people to vouch for you... moreover if you have strong ties with proff. at Michigan , you can always undertake projects with him even if you are not in his research group... also, believe me, once you are bored with one place/ city it starts effecting your work aswell... so make a fresh start at Cornell..