Build Advice for future proofing new gaming system

Approximate Purchase Date: Pricing out now, will start purchasing a s soon as this weekend

Budget Range: $2500-3500 USD

System Usage from Most to Least Important: Gaming(WoW, BF3, Star Wars, Civ), encoding vids, watching movies, surfing the internet

Parts Not Required: keyboard, mouse, monitor (will be purchasing a second monitor in the near future), speakers, OS, Data Drive

Preferred Website(s) for Parts: newegg.com, ncix.com, tigerdirect.com, amazon.com, local retailers

Country: US

Parts Preferences:

Intel i7 3930k
Asus Rampage IV Extreme
Corsair H100 Water Cooler
2 x EVGA 03G-P3-1595-AR GeForce GTX580 Classified Ultra 3 GB PCIe 2.0 x16 (x2 SLI) (This is probably going to change to the AMD 7970 now)
OCZ 240GB Vertex 3 Series SATA III 2.5 inch SSD Max IOPS 6gb/s VTX3MI-25SAT3-240G
G.SKILL Ripjaws Z Series 16GB (4 x 4GB) 240-Pin DDR3 SDRAM DDR3 2400 (PC3 19200) F3-19200CL9Q-16GBZMD
Cooler Master HAF X (RC-942-KKN1) Full tower case
Enermax Platimax 1200w 80 Plus Platinum
Silenx 120mm x38mm, 18dBA, 90 CFM (upgrade push/pull fans for the H100 radiator)

Still not sure which monitor I want to buy. I currently have a nice, but old, 23 inch HP monitor that has served me well. I am considering an upgrade to a 27" monitor, but realize that I would then have mismatched sized monitors.

I plan to overclock the CPU to about 4.5ghz (if the cooler is good enough) and we will see what I can do with the memory and the GPUs.

I am still on the fence about purchasing a second GPU to run in SLI since we are supposed to get PCIe 3.0 cards this summer. Anyone have an opinion on waiting for the new cards versus diving in with the 580s now? I was also thinking that I could go even cheaper with a pair of 560 tis as suggested here at Tom's, then upgrade to the new 3.0 cards as they come out.

My next question is with quad channel memory kits. If I purchase 16gb now, can I combine another 16gb kit at a later time, or would I have to swap out for a 32gb kit?

Anyone know if Ivy bridge(-E) will fit LGA 2011 in case I want to swap out processor later?

Edit: Can someone who is using Eyefinity chime in on what kind of monitor combination they are using? Thanks!

Overclocking: Yes

SLI or Crossfire: Yes

Monitor Resolution:1920x1200

Additional Comments: Want to keep this system for a s long as possible. My last system lasted 6 years, although I couldn't play all my games the last two.

I realize this is pretty long, thanks in advance for any recommendations.