Biology as a major, and no minor for me.
Who told you particulary NOT to pick a science major? That is the most ridiculous thing I have heard so far. You can major in anyfield; however I say do yourself a favor and major in biology. By majoring in biology, you will fulfill your dental school prerequisites and your major's courses at once. Anyhow, you are going to take science classes such as biology, chemistry and physics as dental school prerequisites. Why not start taking them earlier and get used to them? There are more intense science courses to come in dental school, and majoring in biology or anything close to it like chemistry will make you much more prepared for them and also for your DAT. Speaking generally, people majoring in science [such as bio, chem, etc] do better in their DAT [There are exceptions though]. This way, you will also save yourself a couple of years compared to majoring in arts, business or similar majors. Do not forget shadowing a dentist for a good amount of time, and checking out if you like the career.
BTW, who told you particulary NOT to pick a science major? That is the most ridiculous thing I have heard so far.