When this was discussed in the past, I gave a challenge, find someone who has used both AMD 64 & P4 HT platforms(as I have), and prefers the AMD.
You Wont, ALL will prefer Intel.
Intel's are more reliable, multi-task perfectly (AMD's are VERY Poor), and still run all the games without a hitch, Even if you are running other programs in the backgrond.
GPU is the most important thing for games, put a 6800 in a 2400+ AMD XP and say a 5900XT in a 3800+ AMD64. The 6800 machine will easily out perform the 64Bit machine.