Okay, so just right off the bat, I will always choose an AMD over an Intel. That is just the way that I am. Anyway...
When people review the XP and P4 you have to keep in mind that they are picky. If they say that a P4 is faster at media creation they may mean faster by 4 seconds.
In most tests, the XP has proven just as fast as the P4 and even faster in some areas (though it does get beat by P4 is some areas too). So really the question lies in whether or not you want the absolute ultimate proccesor or if you want the cheaper one that performs the same.
You may also want to wait until AMD comes out with it's newest proccesor, the Hammer line. Check out this link (It's a PDF file)
http://www.amd.com/us-en/assets/cont...esentation.PDF . The Hammer will probably be about the same price as the newest XP's are now and will honestly be better then you could imagine (I hope....).
So in the end, if you can't wait, I recommend going with the XP. It's cheaper and you won't notice the difference (unless you are a complete hardcore techie). You may also keep in mind that, with the money you save going with the XP, you could get even faster DDR333 memory. Just make sure that your motherboard supports it.
But if you can wait, you may want to see what the Hammer is all about.