I would stay away form all of the Q8xxx chips myself. They are "budget" quads. And while any quad would seem like a good idea, they are pretty anemic in other aspects.
As for that machine, it has a G31 motherboard, something that we would never use in a build list, a no-name power supply, and slow ram (don't let the "high speed" tag fool you, its 800mhz).
The 9800GT is ok, but we could do better for the budget. That card is several generations old depending on how you look at it.