Actually, I think ATI's offerings in the mid to low ranger are very poor. The X850GTO and X850XT are goo cards, but seem to be going for slightly more than their GeForce equivilalnt.
But, however, thier high end offering simply blow nVidias out of the water! The X1900XTX is better than the 7900GTX, and is also cheaper to boot, and the X1900XT is still better than the 7900GTX and is even cheaper than the XTX!