That's a great point. Out of Penn's Class of 2011 heading straight to some sort of grad school, nearly 50% go into med, law, or business training. (As you note, 25% go straight to medicine).
Interestingly, at UChicago, only 12% of the Class of 2011 heading to grad school go to med school. Further, for UChicago's class of 2010 and 2009, even FEWER students headed straight to med school (10% for '10, and a remarkably low 5% - 5%! - for '09).
Moreover, the academic slant can be seen for UChicago students - every year, about half the students heading to grad school go to PhD programs or masters programs. While the Penn numbers are vague, it seems as if significantly fewer students are entered phd or masters programs straight out of college.
Finally, dunbar, you mentioned that the pre-med culture at Penn is very different from the one at UChicago. What do you mean by this?