plain and simple. what american ungergrad colleges lean towards ib rather than ap, and vica versa.

particularly stanford, georgetown, duke...

this is such a generic question...if you really want to know you have got to contact the school's admissions people directly. don't want to call? email them.

and consider yourself fortunate to be at a high school that offers AP AND IB. some people have neither.

as a general guideline, try to take the most difficult courses offered.

Just go AP if you decide to apply to Institutions of Public Education. If you want private schools then it doesn't matter because most likely the credits won't transfer anyway.