Ah yes, a PhD... that's exactly what I'm going for now. In Pharmacology, to be exact, meaning I'm studying the mechanism of how drugs and natural substances affect the body. A fun subject, though the grad school program feels a lot like being in a torture chamber as far as work goes. Ah well, I think it will be worth it in the end, so I'll try my best to succeed in this program.
A pointer to anyone currently an undergrad in the biological sciences: DO UNDERGRAD RESEARCH. Believe me, it will help you immensely when it comes time to apply for grad school. I myself had had a hard time getting accepted into a PhD program; I had really good grades, but practically no research experience. The latter is way more important, though it would be a good idea to not get straight D's in your classes either.