Want to upgrade to EVGA GeForce GTX 680 2gb or 4gb, from EVGA GeForce GTX 570s

I want o upgrade my pair of EVGA GeForce GTX 570s to EVGA GeForce GTX 680 so here I wanted to know whether EVGA GeForce GTX 680 2gb card will be a better choice or I should go for EVGA GeForce GTX 680 4gb, in my case I am using four monitors which are in the inverted T and they are 1680x1050, I have been playing games in windowed fullscreen mode and I have not yet used SLI, so I am willing to go with a single GTX680 series and the run all the monitors off with it directly but then I am not sure whether 2G card will be fine for a 5040x1050 res surround setup or 4gb will be the best choice here, so is there anyone who has an idea about the same and can clear my doubt?? Any help regarding the same will be appreciated.

I think that NVIDIA GeForce GTX 680 4GB will be just better as compared to EVGA GeForce GTX 680 2gb , it has been released on 2012-4-18 but then you will have to check out for its availability, if you like gaming then trust me it will be the best choice, many people have been waiting for the same and have tried it out as well and I have come across a lot of positive review of the same:
NVIDIA GeForce GTX 680 4GB Specification
GPU-

• GPU Series: GeForce 600
• GPU Model: Kepler GK104
• Fabrication Process: 28nm
• GPCs / SMXs: 4 / 8
• CUDA Cores: 1536
• TMUs: 128
• ROPs: 32

SUPPORT-

• Bus Support: PCI-E 3.0 x16
• DirectX Support: 11.1
• OpenGL Support: 4.2

CLOCKS-

• Base Clock: 1006 MHz
• Boost Clock: 1058 MHz
• Shaders Clock: 1006 MHz
• Memory Clock: 1502 MHz
• Effective Memory Clock: 6008 MHz

MEMORY-

• Memory Size: 4096 MB
• Memory Type: GDDR5
• Memory Bus Type: 256 bit
• Memory Bandwidth: 192.2 GB/sec
• POWER-
• Power Draw 195 W / -W
• Min Required PSU: 550 W
• Power Connectors: 1 x 8-pin / 1 x 6-pin

Temperature: 98 C / – C / – C
Noise Level: – dBA / – dBA

Yes even I was going to suggest you the same I think that the NVIDIA GeForce GTX 680 4GB will be future-proof, I mean now a days the games are using 1.5GB at 1920x1080, one cal play Skyrim with mods and hit 2 GB at 1920x1080 easily without any issues we just need ton of high res texture mods and run high levels of AA but then as we know that for the NVIDIA GeForce GTX 570's, VRAM is the limit, I really don’t want to keep thinking about the VRAM and that is the reason even I will be getting NVIDIA GeForce GTX 680 4GB and I don’t think that you should have any doubt in deciding which one will be better as NVIDIA GeForce GTX 680 4GB is appearing to be the best so far. Hope that helps.