You are better off with a single GPU than two weaker ones as not all games support SLI or have problems.
Unless you are running a multi-monitor setup for gaming there is no need to get the 6bg version, either of these cards would do. http://uk.pcpartpicker.com/part/msi-video-card-n780tf3gd5oc
http://uk.pcpartpicker.com/part/asus-video-card-gtx780dc2oc3gd5
It's extremely high quality. The price/performance ratio always gets tossed out the window at the high end, but considering the parts you picked it would be difficult to do better if you're aiming for extreme overclocking. Since you can apparently afford it, you might want to go for a Seasonic PSU.
Yeah but I want all the ROG goodies in the Hero.
Is only 8 gb enough?
Yeah but I want to keep things cool if I upgrade to a 4790k or 4930k and the Dark Rock 3 looks boss
Not sure why you need such an expensive GTX 780Ti.
Asus typically puts in the best coolers, ultra durable hand-picked components, and generally needlessly amazing everything into their ROG cards. It drives the price up, but it's not entirely a waste if the person intends to keep the card, and perhaps overclock it further, for a very long time.
Yeah but I want all the ROG goodies in the Hero.
Is only 8 gb enough?
Yeah but I want to keep things cool if I upgrade to a 4790k or 4930k and the Dark Rock 3 looks boss
8gb is enough for gaming. Rendering/editing can use more.
You are better off with a single GPU than two weaker ones as not all games support SLI or have problems.
Unless you are running a multi-monitor setup for gaming there is no need to get the 6bg version, either of these cards would do. http://uk.pcpartpicker.com/part/msi-video-card-n780tf3gd5oc
http://uk.pcpartpicker.com/part/asus-video-card-gtx780dc2oc3gd5