Overclocking 2.4, 2.53 or 2.66

[smahoney]

Building new machine and requesting some valuable input. - I have to build three more for friends.

Assume that money is not the issue for the CPU - any of the three is within the budget. $224 for a 2.66GHz presently.
Mobo is a GB or 875P - looking like the IC7-G as soon as it starts shipping.
Memory is Corsair TWINX512-3200

Goals:
3.2GHz

2.4 at 178 FSB 3204 MHz DDR 356 - I don't think my success rate is going to be too high with this chip.
2.53 at 170 FSB 3230 MHz DDR 340
2.66 at 160 FSB 3200 MHz DDR 320 - how high does this chip go air cooled?

Which of the three CPU's and Why?
Largest Chance of Success?
Most Room to OC?

Thanks?

 

[stardust]

go for 2.66 i've seen it go up to 3.4 on aircooled with 1.65V vcore, the 2.4 is equally as strong but the 2.55 seems to be weaker

 

[Skooter]

i'm curious as to what ram is necessary to OC at 2.4C...obviously 3200, but what ram is quality enough to sustain the overclock

 

[Hanzou]

i'm curious as to what ram is necessary to OC at 2.4C...obviously 3200, but what ram is quality enough to sustain the overclock

Many people have said that you need at least some 3500 ram to overclock a 2.4c 3Ghz+