I think you need to determine the exact model. I note there at least 3 Pentium Extreme 3.2 processors; Pentium E 540 Prescott, Pentium E 640 Prescott 2M, and the Pentium E 641 Ceder Mill.
I'd still go for the Core 2 Duo if your motherboard supports it. They offer better performance, while consuming less power and generating less heat - all at resonable prices.
I recommend you check out
Tom's Hardware Interactive CPU Charts and do a comparison using any one of 30+ benchmarks they provide. I think you will fine the Core 2 Duos consistently come out at, or near the top.