An article in the Washington Post by Health and Science writer Rick Weiss (July 30, 2007), entitled "First, Do the Math" details the results of a study performed by researchers at Harvard and the University of Virginia. Basically, taking an extra biology, physics or chemistry course in high school provides a boost in grade values for the college versions of these courses. But only in the respective field of the course. And no boost is seen in the other fields.
However, taking an extra math course in high school provides a boost in all three areas plus mathematics. More bang for your buck in that plan. The money quote from the article:
"The one thing that helped students do well in all college science was having taken an advanced high school math class. That undermines a commonly held belief that math training is not particularly important or helpful for the study of biology."
I venture the same can be said for an extra college math course, or even a math minor. But, then again, I am biased....