Ok first off, there's a LOT more to ocing than raising volts and base clock.
RAM has an option in the BIOS to set the RAM ratio i.e. on stock of 133 bclk 2:10=1333MHz, 2:12=1600MHz. There's several ratios and can't remember all of them off the top of my head (I think 2:8-2:14 in increments of :2 not sure). Here's a starter guide that I found pretty useful to OC'ing the i7 920.
How To OC the i7
1. How high do you plan to OC. If you just want to normal OC the EVGA E758 or E757 will do fine. But if you plan to INTENSELY OC like above 4.949GHz then you're gonna want to go with the EVGA Classified.
2. Go with the OCZ Gold 1600 kit.
As far as PSU, I recommend the Corsair 750TX.