Gamerj27

The power cosumption for my entire rig is about 450 watts, and with another 780 it would be upwards of 650-700. So i think you should be more than fine with ur psu

One thing i REALLY hate about that WF cooler is that dumb plastic extension sticking out the side that you see when you have it in ur rig. I really dont understand why gbyte just HAD to put the WF branding there. Anyways, Go for the ACX, Ive had mine for about 2 weeks now, and i can honestly say it was worth every penny. It runs cool/super quiet even under full load and ocd to 1176mhz! It also uses a reference 780 pcb so it will work with any titan/780 waterblock backplate :D

Pretty much the same, I would suggest both of these cards, think gigabyte one is somewhat cheaper? You could go for the looks, some people really dislike the new gigabyte cooler for some reason.

there's a pretty negligible difference between 1866 and 1600 unless you're getting an APU.
PSU is probably overkill, but are you planning on SLI'ing, or anything like that?
good cooler, ssd and hdd.
Go for it!