It appears they will. As X-Bit labs writes, ATI is planning some pretty serious price cuts for their X1x00 series cards. The Radeon X1900 XTX will retail for around $549, and the X1900 XT being brought down to $479. Just in time for Nvidia's GeForce 7900 products.
"The Markham, Ontario-based GPU supplier is projected to announce price slash on the Radeon X1900-, X1800-, X1600 and X1300-series products shortly, according to sources familiar with the plans of the graphics giant. The decrease of the prices will help ATI to more efficiently compete against Nvidia Corp.'s new products which release will spur lowering the prices across-the-board."