For the case, just find one you like that has 120 mm fans.  Newegg is a geat place to look as they have plenty of pictures of each case.
You defintiely want a good PSU. Expect to spend at least $80. (and that might be low)
Sell your 9800 pro (still a popular card and should be easy to see), and go PCI-e. I suggest a 6800 GT. Awesome card and is ready for next generation games now.
2X512 MB RAM is plenty for gaming.
Don't bother with SLI. Too loud, too hot, too expensive, and you won't even use the extra frames it gives you. One 6800 GT is plenty. If you really want a little more, just get the Ultra.
			
			You defintiely want a good PSU. Expect to spend at least $80. (and that might be low)
Sell your 9800 pro (still a popular card and should be easy to see), and go PCI-e. I suggest a 6800 GT. Awesome card and is ready for next generation games now.
2X512 MB RAM is plenty for gaming.
Don't bother with SLI. Too loud, too hot, too expensive, and you won't even use the extra frames it gives you. One 6800 GT is plenty. If you really want a little more, just get the Ultra.
				
		
			