As you said you would like to leave the potion open for Sli so up the PSu if there is enough space in your budget. Nothing lower that 850W for 580 Sli. Best would be a 1000W PSU, but a decent make like Antec, Corsair or Seasonic.
Great choice of parts!
GPU: I would recommend the msi 580gtx, and do not run it sli as of yet, single will be completely comfortable at max settings for BF3.
SSD: If you wanted to go for the 120g range i would strongly recommend http://www.newegg.com/Product/Product.aspx?Item=N82E168...
The reading/writing speeds is a massive difference and is the similar in price.
RAM: For a little extra you could grab some higher quality memory that offers great latency http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Go with the 27inch screen - great for your blu-rays and makes gaming better in my opinion.
Everything else looks awesome!
That is a really good build. I wanted badly to get the P8Z68 but got the P8P67 to not break my budget lol. I haven't used the OC feature yet, but that is a main reason why I went ASUS for the MB. Check out the G.Skill Sniper Series. They are low profile and a lot cheaper.
As for the GPU, I think you will be fine. I am running an EVGA GTX 560 Ti and I'm running the beta flawlessly. I haven't even explored the OC features yet. Whether to go MSI or EVGA is personal choice. I went with EVGA because of the reviews and they have better warranty.
Hope that helps! FYI I'm not an expert -- just sharing my first build experience. :-P