Ball State is great - I am looking forward to finishing my BA and we'll see where that will take me.
As far as your computer, I tried the 17" and it was just to big. The 15" is almost perfect for me, not to big, not to small, and LED screens are AMAZING, very bright and crisp. If you are going to be taking your computer with you to class, field studies, you want something that is going to fit nicely in a backpack. Which brings me to another point, My Powerbook died on me because I really did not have a good backpack and case for it, and it took a lot of abuse as I traveled from classes and on field studies to NYC, Europe, etc. Spend the money on a protective case, and buy a bookbag that has a dedicated laptop slot.
BTW - Rhino 4.0 is da bomb. I tend to build a 3d model on my computer and test the materials on it, then render it on our schools computers and basically setup a render station or two and let them render over night. I only use autocad for wall sections and floorplans, so it doesn't really use much memory when you only work in 2D. If you can afford the 2.4 Ghz 15" I would get that, then upgrade to 4GB of ram at like OWC or something, but like I said, if you have the money. I have the standard 2.2 and its more than I could ask for.