Yep the 8 pipelines & 256 memory bus of the 9700 make the most difference.
Oh the XT, well it has "overdrive" which will enable automatic stable overclocking based on the reported temperature of the core (a gimmick more than a feature).
It has 500mhz core vs the 400mhz of the 9600 pro (which will allow for a pixel fillrate of upto 25% more than the 9600 pro).
Reduce power consumption, i think the 9600 pro & XT allow for the use of AI in the catalyst drivers (For increased speed) and Shadow volume rendering acceleration (For OpenGL based games i.e. Doom 3)
But the 9700 non pro is still faster