Dude, i own a macbook, i installed Sophos Anti Virus, McAcfee, and Norton and all they did were piss me off, every time i unextracted a rar file or something it would popup and i got really pissed. All it did was annoy me so i don't use them anymore.
As for pirated software, i can assure you there's lots, and believe me that all the pirated software is actually very very good.
Also to mention, with a mac, you can go into something called "front row" and this takes you to a whole new dimension of your mac. It's like windows media however, the mac one only requires 6 buttons whilst the windows has 45 buttons on it's remote. Anyway, here you can watch your movies and watch the latest movie trailers all streamed from the apple website.
Also, Apple's "Software Update" makes sure your mac is up to date with the latest security patch's and bug fixes and has fixes for all your applications.
I have to say, there are also loads of amazing features in the OS which do all kind of amazing operations.
If you want Mac OS X on your PC, there's hacked versions, i don't want to give you a link to them for certain reasons but they're called "iDeneb" and another one is called "iATKOS"
Enjoy for what Apple has to offer, they are not totally limited in terms of hardware, you can upgrade most of them with more ram or a better hard drive yourself no problem and i love the firewire