It's really hard to say what the right number is for MCAT and GPA, but I just saw a nice website that can give you a better idea of real world experiences:
mdapplicants.comIt seems like they have a lot of data, and you can search for specific criteria you are interested in - such as people who have gotten accepted into medical school with a GPA between 3.0 and 3.1
People have gotten in, but when you look through their information you'll find a large variety of stories. Just a quick scan I did it seemed like several went to DO schools instead of MD. Also, some had other careers between college and applying to medical school, or they had some graduate school experience.
The bottom line is that you will do the best you can on the MCAT and then you'll have to see if you are a competitive applicant at that point.