cb8539 :
I have a BenQ XL2420T 120Hz monitor for gaming and a dell 24" 720p monitor for other programs. I am staying with 1080p for the time being.
DON'T WORRY ABOUT THE VRAM. I see that the 780 6GB as likes0079 had said would be ideal for high-res gaming, but because the 780ti is so powerful, it won't break a sweat. It's not like a 760 4GB where you believe you could actually play at 4k (not really...you won't get much fps).
Just remember that more VRAM=better quality, and a better card=more fps. It's either performance or quality and since you are gaming on a 1080p monitor you'll get both with that beast if a card.
Btw, it doesn't matter which card you get when it's with the reference or non-reference cooler. Get the reference for looks and OK temperatures as well as the planing of SLI now or in the future or get any EVGA ACX cooler (it doesn't matter) if you are only going to be using one card and want better single-GPU temperatures.
Here's my advice for the non-reference cards-get the one with the highest clock speeds if you don't want to spend time overclocking and just want better performance out of the box. Like the SC ACX or the Classified non-reference (if you can spend a bit more).
It doesn't matter what cooler you get and you won't have to worry..every card is powerful and awesome on its own and even reference temps will be good. I've seen a lot of people get reference coolers for their 780ti. As a personal preference, I would get an ACX card but it won't matter what you get. An ASUS 780ti would be the best IMO with DCUII.