If he doesn't game he won't need anywhere near a 7800GTX...ever
I don't know why the hell you people suggest such ridiculously stupid ideas such as watercooling and G.Skill, if he can't build a computer he clearly won't be overclocking it anytime soon. I also doubt he's comfortable enough to perform the maintenence of filling/draining a loop every so often.
When you deal with clients like I do everyday, you always get people with deep pockets. I ask them what they need to computer to do, and most of the time they don't come close to spending half.
But yeah, the chance of a computer lasting eight years is slim to none. Let's flash back eight years from now, can you really picture a >P2 performing well?
They are not going to support it, either. There is a reason they skipped DDR2, prolly because it sucks, but they are going to go straight to DDR3.
AMD will be moving to DDR2 in early 2006 upon the release of their newer sockets, namely M2. The DDR3 skip was a rumour that AMD denied a few days after it was published