I'm confused. Most of the components that you list are "deactivated" at Newegg: old, and no longer for sale. (Also, OCZ is getting out of the RAM business, if they aren't completely out yet.) Do you already have these parts from some other source?
There are still motherboards for sale at Newegg that support Core 2 Quad CPUs and DDR2. USe the "power search" function. I have no personal recommendations.
If you wish to go with an I7 CPU, you wouldn't be able to use a Socket 775 motherboard (as needed for the Q6700). The I7 comes in Socket 1366, 1156, 1155, and 2011. (I list them in the order they came to market.) You'd also need DDR3 RAM.
If you'd like to build a system based on current components, I'd suggest an I5-2500k, a Z68 (Socket 1155) motherboard, 4 or 8 GB of DDR3-1333 RAM, and a more up-to-date graphics card like a Radeon HD 6850 or nVidia 560ti based one.
As regards the sound, most motherboards come with onboard sound. Many of them support 7.1 analog sound. The analog jacks are typically 1/8" (like for earbuds), so you'd need an adapter cable to use the 1/4" plugs on the speakers. (I'm surprised that they don't use RCA jacks, but I don't know much about audio.) Example: Amazon.com: Hosa CMP159 10 Feet Speaker Cable, Y Cable 1/8 Inch TRS to Dual 1/4 Inch TS Cable - 10 Feet: Musical Instruments
(Stereo 1/8" to two 1/4" mono.)