The following is a recent TED talk by Francis Collins explaining how drugs are made, how they could be made better, and why new drugs are needed.
This video can also be found on the TED website here. The comments section underneath unfortunately attracts a few of those who believe that all you need to be healthy is to eat well (i.e. vegetarian) and exercise, and that pharmaceutical companies are evil. Though it is nice to see these claims being vigorously countered by those who eat healthy and exercise, yet still need drugs to treat various conditions.