Not quite that cut and dry, I'm afraid. To run a Conroe chip, he would need to spend more money on motherboard which is $200 give or take some, and a stronger PSU ($100). I'm not denying the Conroe is going to be good value, it's just more than you're thinking of.
Add all of that to the fact that Conroe is brand new technology, Intel is probably still working out bugs from it. AMD is at its peak right now, making some of its best chips right now, it's a simple and trusted choice.