My Chicago GPA was 2.99, GRE (at the time I applied this year) Q780, V710, A 4.5 and I got in Boston University. I was waitlisted at Brown. You can probably do much better than that. I took some harder math courses (honors analysis, topology, etc.) but my math GPA was about 2. Whether you get into top 5, top 10, or top 15 probably has to do with how well your professors know you and what they'll say in their letters.