go for the 750/100. the 667/133 is a bad overclocker.
with the 667/133 you are basically looking at around 750/150 tops.
with the 750/100, you are looking at least 1000/133 with default cooling, and 1100/150 with more advanced cooling.
also, the 667/133 requires vc-sdram fro the via chipset, and it's not really transferable to a bx mobo.
your best bet would be a 700/100 cB0 stepping. you'll be able to hit 1000MHz with it also with pretty standard cooling.
also, make sure you have some good ram, preferrably crucial, mushkin or mosel vitalic. all of them should get 150 with cas2.