MAC vs PC for a developer?
godDLL: 1)  You just did.2)  Intel/Mac or Intel/Linux, so you can run IE6/7 in a VM/Wine.  Macs are lower maintenance.3)  TextMate/Coda or Xcode (or Scribes in Gnome) will be your definite friends, as well as Terminal and Firefox/Safari's debugging features.      
Python and the relevant libraries come with both systems and are easy to add to.4)  Would not recommend any Windows version for doing either development or design.  Or anything mission-critical, for that matter.  
All the software you need comes with the Mac in the "Developer Tools" package on your Leopard DVD or in the public repositories for your Linux distro.  You'll find many more choices are available, and you may even fall inlove with some.Major disadvantages of a Mac over PC would be that the hardware is mostly set in stone at the time of purchase, which can, even if rarely, become a nuisance.  There is some very strong classic gaming going on on the platform, but new titles often go on by not noticing OS X, which can be a bummer if you like your machine to be your do-everything, including being a gaming console.  
There are no disadvantages in relation to development, however.And now for something completely different:  don't let them buy you a Mac if you won't own it when they do.  That is, there will most probably come a point when you'll want to own it.