Well, It all depends on what OS is he going to use. If he wants to go 32bit, that setup would be optimal for it, but if he would want to go with a 64bit OS, then 8gb of cheaper memory would be optimal. It all depends on his intended use of the machine. And as for the sound card, I am not too familiar with the other brands, but I am fairly happy with my X-FI Extreme music.
I definitely hear you on that one, but if he's going for that bad ass rig, chances are he's going to want to use Vista. The reason I have mentioned the alternative sound card, is because Creative is horrible with Vista support, especially x64, which would be optimal due to 8GB of ram and no page file. No page file sounds so, so good to me.