If you get a Mac you'll have to also get Windows to dual boot. It is a requirement for the college of architecture since a lot of the software doesn't run on Mac. I'd just get a windows computer and save the hassle, especially since they're cheaper for the same product anyway, but it is up to you. The actual requirements are here:
2009-2010 Virginia Tech Computer Requirement
It looks like you have to have Vista Business, but you also have to buy the software package from them which may include Vista Business (the Engineering one does.) I wouldn't go out and buy any software until you look at the package you get from them.
