Mac laptops are cute and all but I don't know how easily you can find software for what you need on OSX.
Mac these days are pretty decent in terms of price/performance...and the whole total cost of ownership thing. Pretty much all of Macs machines (laptops/desktop/subdesktops/servers) are all using Intel chips now. So you CAN also install and boot up Windows/Linux if you'd like. I have a Mac laptop for almost 4 years now *without* a single issue. I don't even have to shutdown my laptop, all I need to do is close the lid, and when I open it 1/2 hour, a day later, it immediately comes back (no need to wait for it to boot up, etc.)
Don't forget that you get all the cool apps to play with your songs/pictures/digital movies that come completely free with the computer.
Mac OS X is Unix based so you get all the tools necessary for unix developmet, vi, emacs, c++ compiler (gnu), java, python, ruby, subversion, the whole nine yards. It also comes with XCode IDE, which is the a C++ development environment just like Visual C++, except, again that it comes pre-installed (free) with the computer. I think there's also versions of Mathematica, MathLab, Maple for Mac OSX as well.
The entry level MacBook is a *beautiful* 13" widescreen laptop, Wi-Fi (wireless), Ethernet, Blue-tooth (to connect to your phone) ready and comes with all the softwares that I describe, and costs $1049 (with the student discount). The regular price is $1099. Below is a snippet of the specs from Apple.com
Oh, there are also alot of cool features in the upcoming version of Mac OS X (Leopard), which is the reason I'm holding out on buying a MacBook right now....it's going to be just awesome!
http://store.apple.com/1-800-MY-APPLE/WebObjects/AppleStore.woa/wo/2.RSLID?mco=A4791B5D&nclm=MacBook
Intel Duo Core processor
Built-in Isight (webcam to be used as video chat/conference)
FontRow / Apple Remote (to be used as a media center with your TV)
13.3-inch widescreen display
1280 x 800 resolution
1.83GHz Intel Core Duo1
512MB memory (2x256MB SODIMMs)
60GB 5400-rpm Serial ATA hard drive2
Combo drive (DVD-ROM, CD-RW)