If you're going to spend that kind of $ already on the hardware, why not go all out and get the dedicate GPU.
I don't pay game either (ever), but I do lots of photo/video editing (Photoshop CS2 and Premiere Pro) using laptop in sig below.
Even though it's on board GPU, but it's got a dedicated RAM plus I can dedicate another 128meg to it if I ever need it.
In either of those program I never had any difficult with files that I'm working with.
Opening a file or rendering...