Well, you should wait a few weeks. Just until the X1800XT's are available. Which will be November 5th. All of the current reference cards have been benchmarked and are showing amazingly high performance. I'm not saying the 7800GTX isn't good, because it is, but the X1800XT 512MB is looking at least 25% better across the board.
NVIDIA fan boys relax, before you start freakin' out. I'm not an ATI fan boy, so don't even start. I like both NVIDIA and ATI. I'm just going by the numbers.
Even though the 7800 series was released first and Blah, Blah, Blah... The 7800 series has now been slowly proven to have many problems. Yes, the X1800XT could have many problems too. That's why i'm suggesting to wait. Right now, it's just a matter of comparing the 7800 series problems to the X1800 series problems. That's JMHO.