On the intel build. I would move up to the Pro series 840 TLC isn't a strong flash over time the MLC flash of the 840 Pro will prove to have longer lasting performance over time.
Also, unless you have specific audio needs I would stick to your onboard audio. Reason being is unless you are using anything with a s/pdif connnection or RCA then it would make sense otherwise the onboard has enough.
Also you can save a bit on the PSU. XFX makes seasonic OEM based PSU's.http://www.newegg.com/Product/Product.aspx?Item=N82E16817207013
I also don't have an issue with the keyboard although I personally prefer a mechanical keyboard. But I also understand they are normally a bit more expensive I got my 710+ plus on sale for around 100 dollars. http://www.newegg.com/Product/Product.aspx?Item=N82E16823126299&Tpk=logitech%20mechanical&IsVirtualParent=1
In terms of memory I'd say you are fine you can always in the future purchase more I'd say 16 would be a good spot for you. And beyond 16 you would need pro of ultimate of windows 7 assuming that is what you have.
I would say the same sorts of things I see you went with the 660ti which is a stronger card however I still feel the intel build is stronger. And in terms of cases that is a personal choice on your part I would get the fractal design define r4 because I feel like you get a lot of premium case design for a fraction of the price plus it looks really classy and clean but again I'm not you