Oops I was about to tell you to just go with one 670, but I just saw you got a 120hz monitor there. Very nice! A world of difference between 60hz & 120hz. The Sammy s27a750d is the best 120hz monitor out there for 2d. But if you care anything about 3d or just want to try it out sometimes go with the Asus VG278HE. New model goes up to 144hz! The Asus line blows away the Sammy for 3d. Sammy has a little bit better 2d pic though.
+ 1 for 8gb ram.
The H100 does beat the D-14, but its not by a whole lot. The fans do get loud when at full blast on highest settings. If you want the absolute best performance, without going to a water loop, then go with the H100. If you want the quietest performance go with the D14. Noise doesn't bother me cause I either have my surround system turned up or headphones on.
I myself wanted more performance so I returned my H100 and got a XSPC Raystorm water loop. Now I run my 3930k @ 5.1ghz with my temps maxing in 50c in BF3.. But I need a high OC for my 4-way SLI. You can get a complete XSPC water loop for @ $150-180 that will blows away the H100 or the D14.