not to thread jack but I was wondering where you get the 9800se AIW, and does it support dual monitors like the 9600 AIW?..
Anyway my input to your situation would be to get a 9700np or p. If you lounge around newegg refurbs you can score one for around 160, or look for someone selling one used in FS/FT forums. I don't believe the XT's are really worth it honestly. There the exact same architecture, just slightly slower speeds, the advantage over a pro is only 5-10% at most, and when OCing the two cards the 9600p should have more headroom so the difference will be more around the 5% mark.
If your set on those 2 options I'd go with the 9600XT though, a 9800se that doesn't softmod is worthless.
See this review at Hexus.net - appears that 9600XT and 9800SE perform on a par with each other, but successful soft mod blows away the XT!
I've just bought an Asus 9600XT but if I'd know about the 9800SE softmod before I might have bought it instead...