http://www.ncix.com/products/index.p...s&promoid=1021
This. Brand new processor from AMD, it's a good cheap quad-core that doesn't break the bank. It'll keep up with the Intel Q8200 which is almost as expensive as the bundle!
The 785G has an integrated Radeon HD4200 which is fairly decent, and has HDMI output for your TV. If you need a discrete graphics card, pick out another ATI card and it can do "Hybrid Crossfire" which is like a poor man's Crossfire.
If you are using DDR2 memory, you can recycle it for this machine. Otherwise you can buy cheap DDR2 sticks for $30 or so for 2GB ($50 or so for 4GB, which is recommended if you have Win 7 x64 or Vista x64 installed).