Just so you know, crossfire 5970's doesn't appear to work very well - or at least not consistently. This isn't my experience but there's a 2 page thread on it. Might want to consider reading up on it before dropping $1400 on a pair. A significantly cheaper option that would still destroy all games is crossfire 5870s.
Can't seem to find the thread, could you give me a link ? What I've read so far is that the drivers for the 5970 are still developing and I'm hoping they introduce better drivers to fix this issue if what you're saying causes significant problems. Cuz I was considering to crossfire 5870s but got convinced to buy one 5970 now and crossfire it in a couple of months after price drops =/. Then again, would a 1000w power supply be sufficient for 5970 crossfire + eyefinity + i7 930 clocked at 4Ghz ?