I would get the ASUS one.There isn't really much difference between those 3 cards,but the ASUS has great cooling for graphics cards.
However,Gigabyte is the best for GTX cards.I was able to find the Gigabyte GeForce GTX 780 Ti on your site.It's cheaper than these three and has better cooling that them.I would suggest the Gigabyte GTX 780 Ti.
https://www.komplett.no/gigabyte-geforce-gtx-780ti-3gb-physx/803534
Yes,your motherboard is enough for the GTX.
Make sure that your power supply has two 8-pin connectors.Without them,you won't be able to power the card.
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