Wellesley vs. Brown vs. UPenn

I never thought I would be in this situation, but here I am.

Up until Ivy day I thought I was going to Wellesley. I didn’t think I had a big shot at any of the Ivies I applied to, but I ended up getting into both UPenn and Brown.

I plan on visiting all three again (Wellesley COC, Brown ADOCH), but I was wondering what others think about this situation. How different would my experience be at Brown or Penn vs. a small top LAC like Wellesley?
Career wise, how would any/all of these schools help to propel me forward?

I am interested in Middle Eastern Studies, Arabic, IR etc. I am also very interested in Politics. My prospective majors at the three colleges are as follows:

UPenn: Modern Middle Eastern Studies or PPE (Politics Philosophy and Economics)
Wellesley: IR w/ Poly Sci or Econ (possibly might try my hand at Comp Sci as well)
Brown: IR (fantastic program with focus on Security & Society or Political Economy & Society), Development Studies

Do you want a single sex or a coed school? (That will be possibly the biggest difference.) Do you want division requirements or no requirements (Brown)? Do you want a small college with lots of class discussions and close relationships with the professors (Wellesley) or a large college with world famous lecturers and cutting edge research? Does one of your potential programs you listed excite you more than the others? Visit and see what ‘feels’ best. You will get a fantastic education at any of the three.