The $67 Celeron 566 is Intel´s current overclocking champ. As long as you have adequate cooling and a motherboard that can up the CPU voltage, getting a 566 to 850MHz is well in reach. Some more adventurous souls out there might also want to try taking a Pentium III 700MHz chips up to 933MHz by upping the FSB from 100MHz to 133MHz, but its not as easy an overclock. At $215, the Pentium III 800B still looks like the best non-overclocked bargain on the Intel side, and it will perform like a champ matched with an i815E motherboard, though if you want to cheap out a little, the 733MHz goes for a mere $172.