Ah the only video editing I will be doing will be recording for comp requests and whatnot so I don't think I've much to worry about in that case! Thanks lads!
You shouldn't ever need more than 8gb, but it allows a lot of lee-way when you accidentally load up Arma3 with 7 other games . Go for 16gb, it shouldn't be that much more in cost, and can be well worth it.
But you can always go with 8, and then buy some more.
Also, are you building your rig, or buying it whole. It can be cheaper to build it yourself, I have done it for mine first time with no problems. Got a nice video that goes through it step by step if you were going that way too.
What you getting?