That's what I've read too: the 9600GT is the recommended level of graphics card. i.e. it should run Starcraft 2 well, maybe not top graphics, but something pretty decent.
It does also appear that the GeForce FX is the bottom end, but I wouldn't go so far as to say that the 9600GT will dominate. I think the GeForce FX will run SC2 in the barest sense of the word.
Does any one know what the performance difference is between a 9600GT and a 9600M GT?
When they ran SC2 at E3 or something they used a very high-end gaming laptop, with a graphics card way beyond the 9600M GT, granted this is not surprising at an event like this because they want to showcase the best this game can offer. However, it gives a general idea of what it might take to run the game at max, even if it is a little overkill.