My default reaction, both as a Mac user and someone who knows what perils laptops in competitions face, is to investigate a MacBook running Boot Camp. I have an iBook, the MacBook's predecessor, and it's a rather sturdy device. With the MagSafe connector that Apple introduced with the new Intel models, you have even fewer things that can go wrong (and who hasn't tripped over a wire or two at a bad time in the pits?). If you're going to do a lot of CAD work, I'd recommend optioning up to 2GB of RAM; going third-party on this would be highly recommended.
MacBooks start at $1099, but the education discount (available to K-12 institutions) knocks the price to $999 for the base model. I've seen refurbished models (you can't tell the difference, except for the box) go for $899 in
the refurbished section. eBay might make it cheaper still. Getting AppleCare would be highly recommended--think of it as a $249 insurance policy against a student who still had a little much pizza grease on his hand. The school may have a site license for Windows that would cover the new laptop; failing that, a full version of Windows goes for around $150-200, depending on the site and version.
I've also heard good things about the Lenovo (formerly IBM) ThinkPad line of notebooks, but haven't had any degree of seat time with one.