Ok Mac people...what kind??
Get a standard MacBook, but with the upgraded drive (CD/DVD burner). You could do the RAM upgrade, but it's better to do that after market.
Here is why, with the increased RAM, a MacBookPro is not necessary: Both computers have the same configuration other than the graphics card. MacBookPro has a dedicated graphics card that helps for things like design, gaming, and the like (my brother uses it for 3D rendering of his chemistry research results). The rest is the same (other than the case and screen size, but IMO not worth the extra cash).
Since what you will likely need it for is internet, word processing, and taking exams, the graphics card is irrelevant, so you can save some coin. Also, the MBAir does NOT have a CD drive, which would piss me off endlessly. And, again, WAY WAY WAY pricey.
The coolest thing about the new Intel based Macs is their ability to run Windows operating systems either instead of or alongside the MacOS. Using "BootCamp Utility," you can partition your hard drive, install Windows (if you own it), and boot your computer in either Mac or Windows. With "Parallels" you can run Windows and Mac simultaneously. I have yet to do thism but my brother loves it. He makes the Windows system info transparent, so he only sees the desktop icons. This way, he can run his Mac and Windows based software side by side. Another friend keeps the Windows taskbar visible for easy program access.
Get a MacBook. Versatile. Cool. Just plain awesome!