i would suggest getting an Phenom FX or Phenom, at least an 780x mobo to support 2 graphics cards *RD790 is crazy*. I cant believe i wanted the RD790 so bad that it's not worth it, lol stupid Wildside *palm to face*.
if ur going to stay with intel n want a true quad-core from them, since reading about the Q6600 is just 2 E6600's together, i suggest waiting for Penryn, it will be 45nm, which will be considerably OCable.
if money isnt an issue, then i suggest just getting the RD790 from AMD, 2 high-end Phenom FXs, 1 or 2 HD 2900 XTXs, that X-Fi with 64 VRAM, PhysX Accelerator for Crysis or other games *for me, Hellgate: London*, Hitachi 1TB 7200 RPM HDD, Raptor 36GB 15,000 RPM HDD, n last but not least, Artic Silver 5 thermal paste, and a full tower of ur choice.
P.S i highly not recommend the last paragraph, because that is my ultimate dream computer that will never happen with me lol.