the 8800 ultra is a bit over priced, just get the 8800 GTX's and have some fun overclocking them...
Also, judging by your pieces parts, you have the Striker Extreme or the P5N32-E sli motherboard ?
If so, you definately need to get some aftermarket cooling on your NorthBridge. I got the EK chipset blocks as well as the mosfet Asus-1 blocks. Mosfets not nearly as essential as the chipset, I just got them for peace of mind.