GTX 680 2GB or 4GB

I will be upgrading my GPU soon and am trying to decide if it would be beneficial to go with the 4gb GTX 680 over the 2GB variety. I am currently running 1 ASUS VG248QE but plan on adding 2 more in the future. I know the 2 GB will run great with one monitor but will it restrict me down the road when i add additional monitors. Any input would be awesome! 

with 2gb for single monitor is perfectly ok. If you want to go surround, get the 4gb version, you will need it if you want to keep your FPS above 40+.

get the 4GB to start. Running 3 monitors though can be REALLY taxing on your gpu. If in the future you can add another 680 that'd be even better to push max @ 1080 3x.

I have a 4GB 680; I am currently only running a 1080p monitor, but I am definitely upgrading to SLI and a 2560x1600 monitor this summer; the 4GB will be a huge benefit, but for the money, 7950 CF is the way to go. It may not be as luxurious as a 680 4GB, but 7950s are monsters of cards, and will kick the ass of a single 680 when you have CF.

I am only getting a single 680 for now but definitely want to have upgrade potential to go 2 and then 3 way sli in the future. I want to have a solid base that wont hold me back and dont think the 7950's would be as "future proof" if i can use that term. I think the 4GB 680 will be a good start to go 2 and then 3 way with. 

7950s are already more powerful, or equivalent, to 680s in most situations. 7970s are a good 10-15% stronger than 680s, in fact.

Honestly i am just basing my opinion on a handful of reviews and some bench tests like this one http://www.anandtech.com/bench/Product/550?vs=555 where it looks like the 680 has a bit of an advantage. What is your experience that makes you think the 7950 is superior? Sorry but i am getting all the information i can before i order the card next week. 

Plus i hear amd's crossfire driver support is terrible and if you want to run 3 cards forget about it. 

690>7970>680>7950