I now have the scythe Orochi, or SCORC cooler.. It is basically the biggest and most silent ne on the market. Once I put better fans on this thing, it will bee amazing.
Glad you didn't get a pre-built though.
I don't really see a use for the 4870x2 though, unless you are going to have dual HD monitors or something.
If you stick with one, a single 4870 should be fine.
But man, that's an awesome rig...