Help! I want to upgrade my PC!

Hi, I would like some feedback for my idea to upgrade my PC. I purchased my PC around December, 2015. Now I would like to upgrade it.

The current specifications are:

Motherboard - Gigabyte GA-Z170X-Gaming 7 Motherboard
http://www.scorptec.com.au/product/Motherboards/Intel_Socket_1151/60198-GA-Z170X-Gaming_7

CPU - Intel Core i5 6600
http://www.scorptec.com.au/product/CPU/Intel_Socket_1151/60352-BX80662I56600

CPU Cooling - Corsair Hydro Series H55 Quiet Liquid CPU Cooler
http://www.scorptec.com.au/product/Cooling/CPU_Coolers_-_WATER/48713-CW-9060010-WW

Graphics - Gigabyte GeForce GTX 970 G1 Gaming, 4GB
http://www.scorptec.com.au/product/Graphics_Cards/NVIDIA/56374-GV-N970G1_GAMING-4GD

Memory - Corsair Vengeance 16GB (2x8GB) 2133MHz DDR4
http://www.scorptec.com.au/product/Memory/DDR4/60230-CMK16GX4M2A2133C13

Power Supply - Corsair CX750M Bronze 750W Power Supply
http://www.scorptec.com.au/product/Power_Supplies/ATX/48830-CP-9020061-AU

Case - NZXT Phantom 820
http://www.scorptec.com.au/product/Cases/ATX/48054-CA-PH820-W1

Storage - Seagate Desktop HDD 2TB, ST2000DM001
http://www.scorptec.com.au/product/Hard_Drives_&_SSDs/HDD_-_3.5%22_Drives/44675-ST2000DM001

Optical Drive (x2) - Samsung DVD Drive (Unfortunately Scorptec doesn't sell them anymore)
http://www.centrecom.com.au/samsung-sh-224dbaubs-24x-speed-oem-dvd-rw-drive


I want to upgrade my PC now, and I would prefer if I bought all of the parts from either Scorptec or Centrecom (as I live in Melbourne, Australia) and would prefer if I could get them locally.
What I use my PC for is gaming, recording videos and editing/rendering.

I would like to know if getting these parts are worth it, if not, are there any parts that could substitute these and have a good effect. I don't know a great deal about computers and their systems but I do know that the motherboard I purchased can support up to 64gb of RAM on 4 different sockets.

With that information I looked around Scorptec and found these two options.

First - Corsair Vengeance 64GB (4x16GB) 3000MHz DDR4
http://www.scorptec.com.au/product/Memory/DDR4/64145-CMU64GX4M4C3000C15

Second - Corsair Vengeance 64GB (4x16GB) 2666MHz DDR4
http://www.scorptec.com.au/product/Memory/DDR4/64153-CMU64GX4M4A2666C16

Does 334MHz make much of a difference? And do I even need 64gb for gaming, or is 32gb enough. If 32gb is enough, then I found these.

First - Corsair Vengeance 32GB (2x16GB) 2666MHz DDR4
http://www.scorptec.com.au/product/Memory/DDR4/63893-CMK32GX4M2A2666C16


Second on my upgrade list is a new Graphics card, as I would like to be able to play Triple-A in high quality.

I was wondering what Graphics Card i should get. I found this one from Scorptec.

First - ASUS Dual GeForce GTX 1070, 8GB
http://www.scorptec.com.au/product/Graphics_Cards/NVIDIA/64953-DUAL-GTX1070-O8G?special=yes

Should I move up to the 1070 or should I get another 970, as my motherboard allows for a 2-way Nvidia SLI.


Third on my upgrade list is a PCI-E card, I would like my PC to be able to connect to the internet and be able to play online games with low latency. I had a look around and I found this one, I'm pretty sure my Modem isn't Dual Band.

First - TP-LINK 300Mbps Wireless N PCI Express Adapter
http://www.scorptec.com.au/product/Networking_-_Wireless/PCI_Express_Cards/43951-TL-WN881ND


Now last on the agenda, with all these upgrades will I need a new Power Supply with a higher wattage amount. I'm not sure how much these new parts need and how it will affect the existing parts. As I've stated ^above^ I'm not very good with computer systems, I just want to improve my existing PC without any problems.

I hope someone can help me, if you have any questions please ask them and I will answer.
Thanks in advance.

Regards, IceMage123