What future needs? The PSU I recommended is certified to run SLI 8800GTXs. That's basically the most powerful configuration today. Video cards are going to start using less power as well, it's just not efficient to suck up so much power.
He doesn't have to no. 32 bit OS'es will not see all of it, but the system will still be able to use it. At any rate, both the 8 gigs of RAM, and 1K Watt PSU are both over-kill and a waste of money.
Yeah there is one on newegg. I think Ihuser has it.
But I wouldn't get 8 gigs man lol, like unless you get every software out there and run it at once. But thats unnecessary.