NVIDIA GeForce 9400M vs. NVIDIA GeForce 9400M + 9600M GT with 256MB

I am purchasing a MBP at or around Christmas. I am looking too use Photoshop CS4 and was wondering if it is worth the upgrade to NVIDIA GeForce 9400M + 9600M GT with 256MB or should I just stick with the NVIDIA GeForce 9400M.I am not able too spend any more than the 1999.00 price point so these are my only two options. I need the portability of a laptop otherwise I would go with the iMac. I am sorry if this has been asked before, I am new too the forums (still trying to figure out the whole navigation thing...lol) as well as

Thank You

Thanks Hellhammer. Another quick question, would the 9400M be able to handle video that I take with a non-pro digital video camera. Just simple editing, splicing stuff like that. Also is their a big difference in the processor speed 2.53 vs. 2.66.
Thanks Again.

Thank You