The basic spec of this PC looks ok but -
If I was buying a PC in order to play games, eg Doom3, the forthcoming Half-life2 etc, I would have a PC as follows -
P4 3.2GHZ, 1Gb Ram, big hard drive (120GB) or two SATA drives if I could afford it. A soundblaster Audigy2 for decent sound and a good set of surround sound speakers.
An ATI based X800 or Nvidia 6800GT or 6800 Ultra 256Mb video card running Windows XP pro. Now if you consider that these video cards can cost between �290 to �400 each, it will put the specification of the machine you are looking at into perspective.
When buying a PC you get what you pay for, I would want to know the make of motherboard, make of ram, can it be easily upgraded. I would definately stay away from a PC that has shared graphics, and pay extra for a decent graphics card.