I highly recommend Mac, rather than Windows. I've got the new (well, new, kinda) iMac, with 2.00GHz Core 2 Duo and 1GB of RAM. It runs smoothly. However, on a Macbook, the graphics don't seem to run as good as on an iMac to me (we just got a new Macbook so I had the chance to try it), so I recommend you take 2GB of RAM instead, to make stuff a little more fluent. It helps a lot when multitasking, too.
The new Macbooks arrived a few weeks ago, they're faster than the previous ones. I recommend the
2.1GHz Macbook with 2GB of RAM (you can choose this option at the Apple Store). As Drolleke said, AirPort Extreme isn't needed because it's already built-in. If you're going to do work for school on it, you could consider buying
iWork '08 as well. It's very easy to use and it has some great tools. It costs $79.
This would cost you $1278.00 (including iWork), I think (you live in California right?).
If you like, you could also buy an Apple Remote for stuff like iTunes and Front Row to play movies and DVDs. That'd be an other $19.
If you're on the move a lot, the trackpad can be really useful, but if you'd use it mainly at home you could connect a USB/Bluetooth mouse. Most USB mice are supported on Mac, so if you still have a mouse from the last few years lying around, it'll probably work.
Hope this helps a bit.

~Knight Haleth