I can also recommend the i7 3930k with the Asus p9x79 but make it the Pro or the WS version of that motherboard. The basic version has some raid limitations. There's a lot of good advice on a build with that processor and motherboard at the videoguys DIY 9 page. I just went through it myself and went with the Pro board and G.Skill Ripjaws Z RAM (you might get better or faster RAM than that – I happened to catch a deal and went with it).
I upgraded from a Q6700 with 6gb ram to the above setup with 32gb ram and my mixed HD/SD to SD video transcodes out of Premiere Pro went from and hour and a half ish for a 9 minute sequence to about two minutes for a 9 minute sequence. Very happy!
Good luck
Frank
Frank Jannuzzi
Atomic Buddha Arts
www.atomicbuddha.com