Dual core 2 or i5?

Im making the jump to a mac laptop... But i have an issue. I like the size of the 13 inch MBP, but it only comes with the dual core 2, whereas the 15 inch MBP comes with the i5. I do heavy photo work but some light video editing. How big of a difference is there with these two processors in this regard?

Do to the nature of your work I would think the 15 would be more suited or at least on
most of the Nikon material I am learning they seem to have the 15.

When push comes to shove, there is a significant difference between these two processors, yes. An i5 will be about 20% faster than a C2D at the same clock frequency. In addition, the 15 inch MBP sports a faster discrete GPU (330M as opposed to the 320M) which will also make a difference.

Definitely enough of a difference that I would personally say go for the i5.