Depends on what you use. Most programs seem better optimised for NVIDIA, but some programs like Blender perform really well on AMD (often beating out NVIDIA). Also depends on what OS. If you use Linux, unless you have some really CUDA specific workloads, go AMD.

The last two cards of mine have been Nvidia. Currently, I have:

CPU: Intel i5 6600k
GPU: GTX 1070 (SC Gaming 8GB)
Memory: 16 GB DDR4 2133

I got a pretty good deal on the card during Black Friday last year. I don't remember exactly what I paid, but I think it was under $400 with a free copy of Monster Hunter World. I'll have to check, as now I'm curious.

well good its just that hearing that these new consoles will surpass the specs on my pc has me wary

although i suppose that's a good thing since this means pc will get good ports that perform well

I actually use blender and it has a render setting for nvidia cards... the cuda setting I think? so i thought the opposite in terms of blender, I'll have to do more research

My GPU history: Matrox Mystique+Voodoo 2 > Riva TNT2 Ultra > Geforce FX5200 > Geforce Ti4200 > Geforce 6600 > AMD Radeon 4870 > Geforce 650ti > Geforce 960 > AMD 580 (for a few days, it was a loud and hot mining card that I sold off) > Geforce 1660ti

My CPU history: Intel Pentium 200 MHz > AMD Athlon XP 1900+ > Intel Core 2 E8400 > Intel i5-4570

As you can see I mostly go team green and blue, but my next CPU will most likely be Ryzen.

so can i do a rig with an AMD cpu and a nvidia graphic card? any downside with that combination?

I believe blender to be more more OpenCL heavy. And of course, AMD has their own ProRender plugin for Blender.

Sure thing, nothing stopping anyone from doing that yet ... 

Unless of course one day every hardware vendor decides to do lock-in like only allow single setup pairings such as AMD CPU/AMD dGPU, Intel CPU/Intel dGPU or Nvidia preventing it's drivers from working on either CPU vendors ... 

That would be pretty much the best combination really in terms of bang for your buck imo, I have 2 different systems which use Ryzen Cpu's and Nvidia Gpus and they're both great little machines. Ryzen1700 with a 980ti and a Ryzen2600 with a older 780ti both machines very capable at 1080p gaming which is all my monitors and projectors use.

Mine is a little different.

S3 Virge DX/XG 4MB > 2x 3dfx Voodoo 2 > ATI Rage Fury Maxx > Geforce 2 > Geforce 4 Ti 4200 > Radeon 9700 Pro > Geforce 7950 GX2 > 2x Geforce 8800GT > Radeon 4870 Crossfire > Radeon 5870 Crossfire > Radeon 6950 (Unlocked into 6970) quad-crossfire > Radeon 7970 Triple-Crossfire > Radeon RX 580 Crossfire.

CPU is just as colourful...
Intel 486 DX-66 > Pentium 166 MMX, Cyrix PR 300, AMD K6-2 300, Pentium 3 667 @ 800mhz, AMD Duron 1200, Athlon 1900+, Pentium 4 3ghz, Athlon 64 X2 4000+, Core 2 Quad Q6600 (Still got it!), Phenom 2 x6 1090T, Core i7 3930K (Still got it!), Core i7 8600K, Core i7 9700K.

My next CPU is likely to be the Ryzen 9 3950X, 16 cores baby. - Should be an upgrade that will last me an insanely long time, it's the next Q6600/3930K in terms of longevity.

I don't have a brand preference, if an offering looks compelling, I will go for it... Same reasoning I use with consoles, hence I own devices from all 3 manufacturers.

Doesn't help that AMD and Intel stagnated in the CPU space for the longest time. So the old Core i7 quads aren't aging very well at the moment, the hex cores should age allot better.

But it all depends how many threads the next-gen consoles reserve for the OS/Background duties and the clockrates that Microsoft and Sony settle on as to how long your current CPU will last. - It still has years of life left in it still either way!