I am still running an old S939 X2 4200 overclocked at 2.8 on a now classic DFI motherboard. The parts from a machine listed below are being sold not too far from me with an asking price of $400.00. What is worth $400.00 today? Is the box with these parts in in worth the upgrade considering they, too, now are a little bit old. I was thinking of going in with a hard price of $300.00 and making it a buyers market. I am ok either way, if the guy wants to hold out for his asking price, but having a new computer to play with sounds like fun... and it is time.
To keep my old parts and upgrade from newegg, I would need a new CPU/heatsink, motherboard, and ram.
Q6600 is about 3 years old now, but still a good CPU. I still have dual GTX 260. The WD Black is still a great hard drive, I wouldn't even touch those IDE hard drives.
Silverstone is a trusted power supply. I'd say $400 is pretty decent, but if you can lower it to $300, you're getting a steal.
This rig would probably be better than any AMD Athlon X2, X3, or X4 setup.