If you've got $2500 to work with, I'd got with a dual socket 1366 board with 2 Xeons. If you plan on using this more for 3D work, then I would get a workstation card instead of a gaming card. nVidia Quadro FX4600
http://www.newegg.com/Product/Prod [...] 6814133213 or ATI FirePro
http://www.newegg.com/Product/Prod [...] 6814195079
But it sounds like you're building a high end gaming machine and it looks great so far, but that MSI Eclipse comes with a X-Fi card already. As for the processor, I would still recommend the i7 920 and overclock it it's really not that different from the 950. If you want to see difference, you've gotta go to to the i7 975 Extreme.
Also, if you don't use this computer for 3D work, then those 12 gigs of ram would be wasted.
What do you have for Hard drives?
Do you plan to overclock? if you do, then you need a heatsink too. Prolimatech Megahalem would do you good.
What do you have for PSU?