Ugh, there have been so many topics on this question already.
Could you be more specific as to which Core 2 Duo Processor the laptop offers?
If you're wanting to purchase a laptop for long battery life and don't plan on doing high-performance functions, the Core 2 Duo SU7300 is a good choice.
Otherwise, if you want more power, then the i3 is better with the new Hyper-Threading. But that's only if the price difference isn't that big.