For the people who say "Why does the Macbook/Macbook Pro need decent graphics capability? Just buy a gaming PC" ---
1) Graphics acceleration is NOT limited to gaming. First of all, the entire OSX interface runs on OpenGL. More importantly, professional video/graphics applications (based on CoreImage and other frameworks) utilize OpenGL for accelerated graphics processing and rendering. Remember the "Pro" in Macbook Pro?? 3D modeling, animation, CAD/CAM, video editing, compositing, etc all need decent graphics acceleration. Even Photoshop is supposedly going to be hardware accelerated in CS4.
2) Apple's OpenCL will make it much easier for applications to utilize the parallel processing capability of modern GPUs to offload certain types of processing.
3) Many people CAN'T AFFORD buying a dedicated computer just for gaming AND a Macbook/MB Pro. They want ONE device that can do it all.
4) nVidia's graphics chipsets have much better hardware HD video decoding than Intel's GMA. The image quality and enhancement features are better (iDCT, deinterlacing, upscaling, etc) and they use a lot less CPU power during decoding. (Even hardware video decoding uses some CPU time.. and the amount depends on the implementation. AMD's GPUs are even better than nVidia in this regard)