i would reccommend core 2 duo's but i totally understand why you would go amd. they are excellent overclockers especially the optys so they are great bang for the buck.
who has a 5.2ghz E6600??
i noticed he has one core deactivated to keep it stable. i dont think that counts. if you have to cripple a chip to OC it then its not a big improvement im my book.