Nvidia's most recent mobile chipsets are expected to cause quite a stir in the integrated GPU market, with some estimating that the 9400M could be a serious threat to Intel's current dominance. At the very least Nvidia is hopeful, and some notebook vendors believe it could end up taking a 20% share of the market. That's specific to platforms based on Intel CPUs, as AMD has a bigger advantage on platforms using their chipsets.
The lower cost and higher performance of Nvidia's mobile GPUs is a huge selling point, and the much better power consumption of newer discrete cards is playing a part as well. The GeForce 9400M has been identified in particular as a chip where the power consumption, performance and price have certainly one-upped Intel's GMA offerings.