[Old_Mil]

And besides, can I grab some old hardware out of my closet and install OSX on it?

Very likely, you can. My mother has a nine year old Powermac G3 that she's running OS X on. I did upgrade the five year old video card in the machine and put in a large, modern hard drive but it is running OS X quite happily. Neither Windows XP SP 2 nor Vista will run happily on nine year old hardware - assuming it will even boot. When people say that Macs have a much greater useful life when compared to their Windows counterparts, they aren't kidding.

[Doohickey]

Cool! So, I can dig out my old Compaq Evo and install OSX on it? Bring it on!

Or...are you just limited from the hardware that you can buy from your OS vendor?