Then give me two comparable prizes to pick from.
The point of this example is to show that the PC is the better value because, from your earlier point, you can get a quad core gaming machine for the same price as the mini plus monitor and Windows. My counter to this is spec out a gaming machine for $599 (excluding monitor) and it will not be a top of the line i7 with high quality Nvidia graphics and maxed out ram/hard drive. It would, rather, be something like this (which is actually more expensive and does not include a monitor):
http://www.dell.com/content/products/productdetails.aspx/desktop-xps-625?c=us&cs=19&l=en&s=dhs
Between the two, I would pick the Mini, no questions asked.
The machine you speced out is not even remotely compatible with your original statment from which this example spawned and is thus a straw man argument aimed soley at getting me to admit that the PC is the better value.
Until you make the comparison a real one - a gaming PC that you can get for $599 sans monitor, I'm not going to fall for the trap.