MacBook for College + Graphic Design

So I'm a freshman studying Marketing Communication but I like designing a lot, and it's time to get myself a macbook. I have a 2009 iMac at home where I do most of my work, and I have an iPad which I use for school matters, but since I'm starting to get lot into design I need a Macbook so I can work anywhere, not just at home, but I also need it to be very portable.

Which one would you recommend? Is a MacBook Air enough?