Shop around. Quick search on Newegg and the Gigabyte z97x gaming 5 is $40 cheaper than the 7. Are you really getting $40 bucks worth in the difference.
I also go a bit overkill on PSUs and usually pay the same amount. Waiting for rebates or sales and you can often get a step or two higher wattage for the same price, or the same wattage for cheaper. I've read a lot about the benefits of headroom on PSU's, keeping load down, reducing heat, etc. But shrug.
Is 16gb really needed these days? I got 8 in my last system late 2013 and have yet to have any issues, and I'm a chronic minimizer, so I'll sometimes load a game, minimize, load internet, min, load a movie, min, then load a new game and never notice a difference. (will say, this is with an i7 which probably makes a difference?)
The concept of future proofing isn't as relevant as it used to be, imo. The product cycles are pretty short and they keep using new sockets and shit. I always recommend people shoot for a respectable mid-high point in parts, avoiding the best of the latest generation. Spend half as much and build a new system twice as often. Or something like that. Spend 3/4ths as much, then build a new system in 3 years instead of 4. What happens is people end up spending more than they needed to under the idea of 'future proofing' and then never get the most out of their system and want to upgrade for all the new tech anyways before they do. You don't wont to hamstring yourself on a new build, but it's hard to do that any level of respectable budget.
Never buy the best of the latest generation unless you just have money to burn and want the best every 2 years, but then the only reason to ask for recommendations is to brag
