What is the lowest level GPU that can run WoW smoothly (60 fps) at 1440p on ultra?

[Lathais]

I use a h100i works great.

http://www.anandtech.com/bench/product/934?vs=915

Performs about 17% better than the Noctua NH-D14 and is over 10db louder while also being nearly 30% more expensive. Not really worth it IMO. If you are going to go water cooling, do yourself a favor and go custom loop not AIO. AIO coolers are just plain not worth it.

[Mythbredor]

http://www.anandtech.com/bench/product/934?vs=915

Performs about 17% better than the Noctua NH-D14 and is over 10db louder while also being nearly 30% more expensive. Not really worth it IMO. If you are going to go water cooling, do yourself a favor and go custom loop not AIO. AIO coolers are just plain not worth it.

It works fine, not that loud but I wear a headset tbh my coil whine is louder. custom loop is a pain in the rear I don't feel like dealing with. So it works for me.

[Ennvina]

Here is where I'm currently at with my parts list:
MSI Z170A
i7 6700k
Nvidia GTX 1080
Corsair CX650M 650W

This looks solid to me.
I don’t know the exact reason, but gaming setups that I see today tend to favor the ASUS Z170-A. Maybe you should look into it.
The 650W power supply is a wise choice. I wouldn’t pick less with the rest of the computer.

I might do liquid cooling but haven't made up my mind and the RAM will be 32gb, HDD 2tb, and SSD 250gb but haven't decided what brand I want on those yet either.

32 gigs of RAM is a lot. 8 GB is enough to play WoW so even if you want to edit videos I think 16 GB is more than enough. I haven’t edited videos recently, though. Maybe the latest video software could make use of 32 GB. About the brand, Kingston, Corsair and G.Skill are popular these days.

250 GB of SSD is very good if you will mostly play WoW. I would suggest Samsung 850 Evo, Samsung 850 Pro or the Crucial BX200. But honestly, don’t look too much at SSD benchmarks. On paper you can find impressive numbers but in practice you don’t really get to see the difference. For instance on paper the Samsung 850 Pro crushes its sister 850 Evo, but in practice they are almost identical. Since the 850 Pro is much more expensive (about 40%) than the 850 Evo, I would rather pick the 850 Evo.

2 TB of HDD looks good to me. You should plan your HDD capacity based on the how you will manage your videos. If you like storing raw FRAPS files for an entire tier before editing the video, you will need a lot of space. If you compress videos the same day you record them (or if you compress them while recording), you will need much less. The brand doesn’t really matter here. Just pick something that doesn’t melt your beloved files.

About the CPU fan, I really like Noctua. Their color is ugly but it’s inside the box so who cares? Currently I’d recommend the Noctua NH-U12P SE2 (for an i7-6700K otherwise it’s overkill). And yes, AIOs aren’t so great. A good air cooler will perform just as good as a watercooling AIO, and the air cooler will be cheaper and will be easier to install.

[Lathais]

It works fine, not that loud but I wear a headset tbh my coil whine is louder. custom loop is a pain in the rear I don't feel like dealing with. So it works for me.

Not saying it doesn't work fine. Yeah, the performance is good, it's just more expensive for not a lot of gain. Fact is you can get near the same performance from air for less $ and not making as much noise and there is no pump which can fail. Not to mention what would happen if a hose leaked. Let's not forget about maintenance either. Aside from dusting out the case as normal, with a good air cooler, there is nothing additional you have to do.