I second that... Although you'll probably pay more for it upfront, you'll save it in the end with all the extra stuff you have to tack onto a pc (anti-virus, repair tools, anti-spyware, etc...)

Plus it will always work and you get a bunch of cool apps to use: iPhoto, iMovie, iDVD (aswell as iTunes).

Finally, although you can use AIM on a mac, Apple's own version called iChat is way cool ! You have to go to an apple store and play around with them...

Anywho, good luck searching..!