Indeed. But I don't think that the 7900GT should be compared to the X1900XT. They're in different leagures. The X1900XT is more of a 7900GTX leagure player.
As for X1800XT vs. 7900GT, its the 7900GT thats better. But just wait for the X1900XL and we'll see what happens since thats the actual 7900GT contender.