Computer for bio major?

<p>Im going to be a freshman at rutgers and right now i have a Dell Studio from late 2008. It's slow, heavy, and the battery life is about an hour and a half. When i say slow... I mean really slow. I need a new one but i dont know what to get. I was leaning toward a macbook air '13 but my high school has them and i wasnt that impressed. If i was to get a pro it'd probably have to be retina display and that hikes up the cost which i don't really want to pay. The only way i'd get a pro w/ retina is if it lasted like 10 years. As for PC, there are just so many options. Id prefer 8 gb ram, dual core processor, over 200gb hard drive and decent battery life. The most important thing is how long the machine will perform well for me. Whats the best thing to get? Btw i'm comfortable with mac and pc, below 5 pounds, and above 12 inch screen size. </p>