I would then put that money into a better quality PSU as that ultra only provides 45A which would not be sufficient for two video cards, a higher quality 750W unit will provide you with more power (60A vs 45A) and higher efficiency, think of it as an investment that will last you many years without upgrade. http://www.tigerdirect.ca/applications/searchtools/item...
edit: damn i type slow today +1 to shortstuff's build
The apevia only gives you 62A on the 12V rails, isnt 80 Plus certified, and only offers a 1 year warranty against the corsair's 5 year so it is of inferior quality, corsair has a reputation for making high quality PSUs that are often capable of more than they are rated for since they are all tested at 50C.
The i7 920 is a socket LGA 1366 processor, the p55 chipset only comes on boards with the LGA 1156, LGA 1366 boards always have the X58 chipset for now.
The ripjaws will give you the same performance at lower voltage, which means less heat, more OCing head room, and better quality chips from the start. Better chips require less voltage to achieve the same results so a set that runs at 1.5V and has the same speed and timings as one at 1.65V means that the 1.5V one is running better chips. Also keep in mind that you should not exceed 1.65V on the memory for any of the new intel processors or you risk damaging the CPU so the corsairs may not give you much head room for OCing.
Your motherboard and CPU are not compatible because they use a different socket. You have to look and see if the CPU is LGA 1156 or LGA 1366, they are not compatible. The P55 chipset supports LGA 1156 chips and the X58 chipset supports LGA 1366 chips.
I wouldn't waste your time with Nvidia graphics cards. The ATI 58xx series offers higher performance, uses less power, runs cooler, is quieter, and has DX11 support. I don't see any reason to currently buy an Nvidia GPU. The 5850 is the sweet spot IMO.
You're much better sticking with the Corsair PSU. Apevia doesn't make quality PSU's. Trust me, the PSU is not the place to scrimp on quality.
Your case will probably work, it just doesn't look like it has a whole lot of room for a GPU. I've never used it before, though, so I'm not sure.
That Corsair RAM would also work fine. Corsair RAM is usually overpriced, but that kit is at a fair price.