I like this suggestion. For $20 more you'll get a newer, faster chip. The Q6600 is 2.4Ghz stock, where as the Q9550 is not only 2.83Ghz stock speeds, but has a faster bus speed. Overall, the better of the two chips.
The Antec case + PSU is not a bad suggestion. Anything Antec is usually a good bet. They are known for pretty quality products (both cases and power supplies).
As far as AMD is concerned. If you go AMD, do not get anything but
Phenom II. Be sure the "II" or "2" is in there, the older Phenom chips are lesser than the Q6600 you initially were looking at.
And definitely take the suggestion for a better video card if you can budget it in somehow. The 9800GT is a decent card, but is beginning to fall behind with some of the latest titles. So you'd be buying an aging card to begin with. Don't think I'd get anything lower than the ATI 4850 or nVidia GTS 250 these days (in my opinion). Though that also depends on what resolution you have your monitor set to.