Wrong.. the cheapest alienware desktop you can buy is only $799, and it comes with a dual core AMD 2.7ghz, and a new nVidia GTS250, and only 2GB of ram, an alienware instead of Asus mobo, same PSU, etc.
As for your TV, I hope you DO realize that hooking up to an HDTV isn't and never will be as good as a monitor right?
They are slow, and have troubles, and don't have that great resolution at 1920x1080 @ 60hz