What Makes A Gaming Computer?

So much babble on this subject, not much useful to me.  So, like what subsystems matter, and in what order?  Video first.
V-chip or VRAM?
Processor?
Bus speed?
Drive speed?

>>3
I'm still struggling to discern the relative value of the main CPU(s) processor(s) vs the Vcard processor.

I also see that top-end machines oftimes use a stripped array for storage so I/O matters therefore bus speed matters.

I'm trying to define the relationships/ratios.