Macbook Pro 128mb or 256mb Vram?

Ahoy! Mac Users

i was wondering whether its worth to spend extra $500 for the higherend 256mb vram and 2.4ghz 15.4inch macbook pro? Since i am really tight on budget

I will be doing mostly photoshop, video edditing and occasional gaming, is it worth it to squeeze that $500? or the lower end version is good enough? Is there a chart to see the difference in performance or something simmilar?

Thanks in advance