2600K for sure. 900s are ridiculously overpriced now that SB is around. A P67 should be fine; overclock!
For GPU, you'll need AMD if you want those displays (or this http://www.zotacusa.com/forum/topic/3499-zotac-announce...). Without huge-screen gaming, a 6850 should do you more than fine for under $200.
With only one GPU, you'll need around, oh, 600 watts. Why would you think 1000?
Go for a reliable model, like a Corsair Builder.
With the drive, it doesn't matter. Just pick something with solid reviews on Newegg.
RAM: I don't think clock speed matters that much. Don't bother with anything over 1600; 1333 should be fine.
HDDs: SSD! The boot drive should certainly be solid-you put I/O as a priority! I don't know much about picking high-performance storage HDDs, though.
Cabling: The power supply will handle most of everything. You'll need Displayport cables for an Eyefinity setup (monitors).
Sound: Yes. Unless you already have a sound card, which you didn't mention. Normally I'd advise sticking with the motherboard's sound, but not if audio is the priority.
Yeah, without gaming you'll be fine with one card.
Oh, drives. Some will come with their own SATA cables; just check their details first. That won't be a big problem.
Also, even with two cards, unless they were top-of-the-line, you'd be fine with a decent 800.
If you can keep it to two monitors then the on board video chipset on the SB CPU will be enough with a compatible motherboard (either H67 chipset or Z68 chipset).. Yes that is an indirect suggestion to go for the SB over the X58.. As for memory, get two sets of these -