RAM and GFX capability are key here and that means 1366. Sandy bridge (1155) will replace the 1156 boards in 2 weeks but we won't be seeing the "enthusiast" version until late summer. I am assuming this is for a production environment and you will moderately overclock. If ya wanna go big on the OC, then I'd move to a DF-10 case.
That's $2,668 w/ GFX card(s) and whatever ya might wanna strip out.
I put twin SSD's in RAID 0 with a 2 TB drive for storage. You won't need twin fans on the CPU cooler but hey, for the few $$, seems hardly worth opening the case again if ya change ya mind. Again, if ya not gonna OC, then the coller / fans / TIM aren't necessary.
Now for GFX, what ya get is proportional to how many $$ ya willing to fork out. Pick from here between the $450 and $3100 price points
For the CPU you will be wanting something with more cores.
The Intel Core i7-980X Extreme Edition Gulftown 3.33GHz 6 x 256KB L2 Cache 12MB L3 Cache LGA 1366 130W Six-Core Desktop Processor BX80613I7980X is what you're looking for.
The new ATI 6990 with dual processers and 4GB's of memory on each card, (when it come out in about a month), or the NVIDIA's GeForce GTX 580: depending on which motherboard you decide on.
You'll probably also want a work station board. Something like the ASUS P6T7 WS Supercomputer 3Way SLI + PhysX at Real X16 X58 CEB Intel Motherboard or the ASUS P6T6 WS Revolution with NF200 3xPCIe true x16 LGA 1366 Intel X58 ATX Intel Motherboard. Both boards are capable of 24 GB's of memory since you're processes sound memory intensive. They don't have the S-ATA 6GB's or the USB 3 but unless you're running SSD's you won't miss them.