Looking back on it, I would have taken more math, harder physics, and additional chemistry courses. Not so much that you directly use it in biology (unless you go into very specific types of research), but these subjects form the basic principles of what is done in research. Having a quantitative, fundamental understanding or approach can help in more advanced courses such as macromolecules, molecular biology, etc. It surely would have helped me understand molecular interactions and more quantitative approaches to biology.