You probably won't want to wait but this months next generation Nvidia GPUs are supposedly to be revealed and they will probably go beyond enough to the 1080Ti to be worth the wait.
If you don't want to wait, I'll make some suggestions:
If the the build wants to be a nowadays build, 16GB of RAM is the sweet spot, aiming to +3000Mhz memories for maximum performance. An i7 would be the most polyvalent for the CPU. Nvidia cards are just much more powerful than AMD so there's no discussion, and SLIs/crossfires are not recommended. Aim for a nice motherboard, power supply and a SAI to handle correctly power losses and any electric issues. Don't think about water cooling, they aren't mostly worth it and there's the risk of leaking, so just go for a top air cooler. There's no need to put one thousand fans in the case, a pair is more than enough, and choose a case because of its air flow and not how it looks.
The SSD space is really expensive, and I've heard about overheating problems with .M2 ones, so I just would avoid them in big sizes and to install games. A little-256GB .M2 for the SO and programs is more than enough, then go with Seagate's Firecuda hybrid drives for the best performance/price storage solution for gaming, and a standard HDD for data (movies, etc) and maybe one SSD (not .M2) for games which you are gonna play for a long time and that are well known for long loading times. I have GTA V in mind for a perfect example of long loading times game, but maybe you want a 500GB SSD or so for some sandbox or MMO games. Anyway, don't go for a SSD for competitive games like CSGO or LOL because you will anyway have to wait for the other players to load the game.
On the other hand, if you're looking for a long term - upgradeable build and the budget is not a problem, maybe you should go a little crazy with some of the components. Not being experienced in building I would just order a shop to build it and select ultimate tier components, this is 8/10 core Intel processors (i9) and 32GB of RAM. In the future you will be able to just plug a new, much more powerful graphics card than current ones and that amount of RAM and such a powerful processor will still handle it perfectly.
I don't know your country's stores for princing but I think I made a point that shows you two ways to pick a build and how to optimize the money, so I hope it helps