For video cards, I suggest a Geforce 8600, unless your going to be playing games like Fallout 3 at full settings.
He can just put that ram in and it will be fine. As long as he pairs the new sticks closest to the cpu. He should have a 32bit mother board so there should be 4 slots.
Actually when was the last time they made motherboards with 2 slots? I know back in the late 90's when SD was popular mother boards only had 3 slots, but then ddr came around.
If you want an awsome case there is a mac model that can actually hold up to the full 32gigs that vista can use. One of my room mates has it but only has like 12 gigs in it.
Edit- Today is my last day in ct
I leave for florida in like 4 hours.