750w would work but is pretty overkill. A good quality 550w to 650w unit would be more than sufficient. Stick to good brands and models like Corsair, XFX, Seasonic, EVGA.etc - Look at
http://www.jonnyguru.com/ for reviews as they do proper tests of them. You're almost always better off going for a higher quality, lower wattage unit rather than an cheap, high wattage one.
I'd also strongly recommend adding in an SSD, you're building a pretty high end machine so it seems silly to not add one in given how cheap they are nowadays, maybe drop to a slightly smaller hard drive if you don't really need 5tb of storage.
Also, given you aren't using an overclockable CPU/board I can't really see the reason to get an expensive liquid cooler when a basic air one would work fine. The money you save on this would go a long way towards an SSD which would give you a much more noticeable performance increase than a cooler would.
I'd also consider if you really need those 4 case fans - Your case will almost certainly include fans so you'll either end up replacing them or just packing your case with fans you don't really need (which would make it loud and pull more dust through the system). With those parts, all you really need is one decent intake and one decent exhaust fan.
