The thing about technology and gaming specificially is you build a high end rig and 6 months down the track it is just an average rig that wont play the latest games on the highest settings. Personally, I'd cut corners in some places and just put $500-$600 into it each year to keep it up to scratch (which is what I do with my system). Intels latest chipset is a little disappointing as well. It runs hot, has low potential outside of liquid nitrogen cooling. It might be worth holding off until next generation AMD's launch.
-You dont need corsair dominator memory unless youre doing some extreme overclocking, if you want higher speed memory 1600 is adequate. If you are planning on overclocking, get 2* 8gb modules. 4 modules puts more stress on the cpu than 2 modules.
-Liquid cooling, again is only really for overclocking
once you get your vcore up a decent amount. As you cant really do much with the new i7's without them heating up drastically, due to the small area the transistors are located in, I'd suggest not overclocking it at all and just running a noctura air cooler.
-I'd personally go for more space, particularly if you
arrrgh into movies and tv shows.
1tb fills up pretty fast these days. WD 3tb drives arent that much more expensive iirc.
-GPU is massive overkill. A 1gb gtx560 will run most games on >=high. 2gb 660OC is pretty cheap and quite decent.