I beg to differ. The cost difference from the GTX to the GTS is about 25%, and so is the performance difference, from what I gather. Is it worth *getting* the gtx over the gts? No, not really.
I'd rather get a GTS now since this is the first installment of dx10 cards and upgrade to something better later on when there are less possible kinks in the hardware (though seems like its pretty dang solid!).