I'd like it to be able to play Guild Wars 2 and Diablo 3 reasonably well. I don't care if it's on high or low settings. I don't need mouse, keyboard or monitor, just the tower (+graphics card, if necessary) for about $600. I also need it to support dual monitors.
I know the NVIDIA GeForce GT620 is not a great card, but could possibly upgrade it later. I also have the NVIDIA GeForce 8600 GT that's installed in this computer that I could use, but not sure how the form factor will affect that (or if that card is any better, which it probably is not).
My preference is for a prefab build I can slot a graphics card into, but I'm not opposed to building my own as long as it is not hard to assemble (screwdrivers ok, soldering not ok). If I go this way I'm likely to need specific links to components to purchase.
The computer I have now runs both games but just barely. To give an idea of what I'm working with now:
Pentium D 3.00 GHz
2 GB RAM
Windows 7 64 bit
NVIDIA GeForce 8600 GT
Obviously I'd like the new system to be significantly better than what I'm currently using.