does he already have DDR ram?
if not i recommend going to socket AM2, pretty much no price difference, but better upgradeability.
oh and the 3500+ is only a couple of dollars more than the 3200+, so i recommend that; UNLESS - by end of july prices of dual cores drop to the price of single cores, then you'd have to get a dual core! the cheapest crummiest AMD dual core would still be a great processor - so anything dual core would be best!
"Is virtue a thing remote? I wish to be virtuous, and lo! Virtue is at hand." -Confucius