if you overclock the the processor to a better level say 3.2ghz lol really push it and then right a load of ******** about it being dual core=double the speed that most people believe.
I would go with a 8500 or 8600 gfx card instead they are dud cards but most people don't know that and you can push the dx10 next gen factor
you forgot ram vernong your losing it stick in 1gb of no name ram perhaps 2gig if you think its going to help with selling
the problem comes because people in the majority market will want to have vista so you will need to buy vista which will jack up the price of the build quite a bit I would go with home premium. because its PREMIUM most people will think its great