Your answers:
Panther will RUN on anything made since the B&W G3. That goes back 4 years, from G3 to G5 aand everything in between. There are no two versions of it. Same OS will run 32 bit and 64 bit code when available, such as the Photoshop 7.0.1 64 bit code via plugins that Adobe announced will be releasing in the Fall.
One OS for ALL purposes, grandma to NASA! One price: $129 probably.
If you want to find out more, either read on Apple's website or watch Steve's Keynote adddress where he explains how 64 bit works.
The link you posted is not serious and is a biased opinion. He starts by callling OS X a copycat. We all know that is not true and we also know that OS X was released months before XP, and that iits features aare being copied into the next MSFT OS, especiallly the 3D interface which will require much faster new hardware for all of you.
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