if you really wanted to save money in the CPU area, I would go for an AMD AM2 64 X2 6000+ or whichever is the highest now. You won't see any realtime performance differences between them and the way more expensive intel chips (unless you benchmark).
But 6000+ consume a lot more power, and it doesn't overlcock as good as core 2 duo
I recommend E6750 because it is only $40 more than 6000+
Or he could get E6550 if he want to save more money