Most important is the transcript. Within the category of the transcript, for top schools I think course rigor is the most important, then grades. Of course, for these schools, course rigor and grades must both be stellar. But great course rigor where a student challenges herself with a slightly lower – but still outstanding – GPA (say 3.8) is better than a 4.0 and a less-than-rigorous course selection (assuming your school offers more rigor).