Why not get both?
Get the Centrino laptop and get this
http://pearpc.sourceforge.net/
You'll have to buy OS X but this project is for putting OS X on a non-mac platform.
If you'd like to know more, I can look it up or try to explain it a bit better.
Also, going on what TheDave said about a student discount, you could buy Panther, repartition the harddrive and dual boot, which I think I might try eventually...