Well, AMD still generally owns the gaming side of things. Even where Conroe beats the pants of AMD in extreme algorithm based tests, it falls short in gaming benchmarks.
If he wants AMD and AM2, the choices are not THAT easy right now. There are a few motherboards out, but it's hard to pick which is the best. There are some AM2 boards for $125, and others for $250. It's also hard to find a CPU that's appropriate. Finding an AM2 4400+, he will have a rough time. The best stocked AM2 DC is none.. it's hard to find any rate now. The most popular one will definitely be the 4000+ though.
7900GTX is a good choice either way. However, if he insists on going 4400+, he'd probably be better off going with a 4000+ and use the extra money to get two 7900GT's and SLi them.
As for ram.. I'd go for anything in the 2GB PC2-6400 area. I wouldn't pay more than $250 for a kit though.
Foxconn and ASUS' AM2 boards are really, really good. The Foxconn would be my personal choice, just because it's a reference board.