The difference between the 9800 SE, 9800, 9800 pro, and 9800 XT is this.
The 9800 SE has clock speeds of 380/675 with 128 bit memory and 4 pipelines.
the 9800 has clock speeds 325/580 with 256 bit memory and 8 pipelines
the 9800 Pro has clock speeds of 380/680 with 256 bit memory and 8 pipelines
the 9800 XT has clock speeds of 412/730 with 256 bit memory and 8 pipelines
I have to appologize, I was talking about the standard 9800 and confused it with the 9800 SE. The 9800 SE is not as fast as a 9700, it is about equal to a 9600 Pro. They both support DX9. As it is more expensive than a 9600 Pro I can not recommend it. The standard 9800 is a great card however and is equal to a 9700 Pro, but again is as expensive or more than a 9700 pro. To make a long posting short, I would go with the 9600 XT. It is much faster than the 9800 SE