How do you figure it would be a lateral move? You realize that even with current processors they STILL aren't being fully utilized for stuff like gaming and such?I would say that if you purchase a 775 cpu. it would be a big mistake. It would really be just a lateral move.
I would say that identical machines spec wise of which one runs a q6600 and one runs a i5 you'd see a minor improvement in frames.
As someone stated GPU plays a much larger role in a system than cpu.