Over

I have had 3 G502s ranging from the proteus core, proteus core RGB, and proteus core RGB wireless. All of which still work today flawlessly. My original g502 survived cat vomit, cat shit, beer, chocolate milk, and almost 9 years of everyday use. I will say the mouse click will fade over time but its still fully functional but is more mushy. So you probably could get 3-5 years of hard use before it becomes a nuisance 

For me it was very distracting, as you won't have black borders when not using an OLED display. It's more dark grey-isch, especially if you're planning to use an IPS display. But i couldn't justify paying the extra for an ultrawide when some games have to be played at 16:9 and not use the screen real estate i paid for.
 
On the other hand some games worked with 21:9 in ingame scenes and then on cutscenes where the 16:9 monitor would have black bars on the top and bottom, you will have black bars on all 4 sides with a 21:9 monitor. (This happens in Red Dead, Final Fantasy for example)
 
Games like Witcher 3 and Assasins Creed Odyssey also work with 21:9 when running around in the world but switch to 16:9 every time you enter into the dialogue scenes.
 
You can fix some games with mods or editing the .exe files directly using Hex-Editors, but others can not be fixed.
 
I moved away from ultrawide because of that and i've gone back to using two 16:9 monitors again. And it's a relief to not have to think about 21:9 support again. For cinematic games i still have an OLED TV, to which no monitor can compete in terms of immersion. Just my opinion on ultrawide. I don't think it will ever hit mainstream like 16:9 did.

I have a 24" 21:9 monitor and a 23" 16:9 monitor. The ultra wide is my main that I do all my gaming and web browsing and such. I use the 16:9 monitor for videos such as Youtube. It works great. My only regret is I should have bought a bigger Ultra wide, LOL. 
 
On a side note, Youtube doesn't support anything outside 16:9, so that means you will have black bars on the sides of videos when full screen. So Netflix content actually can full screen on an ultra wide and look good. 

I've had a 34" ultrawide and a 24" 16:9 monitor for a few years and never had issues about this setup. But i moved away from ultrawide because in games there are still very bad implementations for 21:9. I found myself looking up if a game properly supports 21:9 before buying it. 16:9 will still be the standard for a many years and ultrawide is a niche thing for people who like tinkering to make it work.
 
TLDR: Can recommend ultrawide for productivity, cannot recommend it for gaming.

stability only if you're having issue with it
latency no
other advantages no, other than armored cable if your cat likes chewing on things (which is super overkill)
yes (again, if it's stable enough for the distance you need, which i think is several meters)

Cat6 would be your best option here. Cat7/8 are really special use case/enterprise/data center type cables. If you wanted/needed the cross-talk/interference mitigation I'd just go strait to OM3/OM4 fiber cable.

Nope.
Yes

No, zero. Cat5e can do 2.5Gbps, so you're way below even Cat5e's capabilities.
Doesn't work like that. If you're worried about signal-integrity and such, you use shielded cable. Shielded Cat5e would still be more than enough. Also, no, it doesn't affect your latency at all. Literally none. That's just not how it works.

Why not go for the latest CPU generation? i7-10700k (basically i9-9900k) costs the same (360 euros in my country at least) and has additional 8 threads.
230 euros will also be plenty to find you a good Z490 motherboard, check this video for recommendations:
 
Also don't forget you can buy Windows 10 Pro OEM (means it will be tied to your motherboard) keys for 5$ off ebay.
Other than that, seems fine, maybe try to find 3200MHz C16 (or better) RAM? Seems to be a tad better than 3000MHz C15 from what I've found in google.
Choose the same parts in https://pcpartpicker.com/ to see if there are any incompatibilities.

Rtings is among the best sources for TV information:
http://www.rtings.com/tv/reviews/samsung/qled-q7f-q7
 
Input lag is fast for a TV. It's a great TV overall, so I think you won't be disappointed. 
 
Viewing angle is typical for a VA panel; don't worry too much about it (unless you have people watching from the sides).

Forget it, I'm an idiot. It was a chrome's youtube extension that was causing the issue.

yes, it is indeed. the hyperX line also has a lot of reputation so i wont be bothered not to recommend them. plus the hyperX cloud 2 are 7.1 surround (i believe)

MSI Gaming: 74°C at 2.3 sone Loudness
Asus strix: 70°C at 3.6 Sone Loudness 
Gigabyte G1 Gaming: 73°C at 4.1 Sone Loudness. (similar Loud as the FOUNDERS)
 
Asus and Gigabyte are pretty bad on the GTX 1080 series.
 
Gainward Phoenix / Palit Jetstream/Gamerock: 71-72°C at 1.5 sone Loudness
Zotac AMP! Extreme: 75°C at 1.7 Sone Loudness.
 
 
So, Gainward/Palit > Zotac AMP! Extreme > MSI Gaming. When it comes to pure Loudness / Temperature ratio.
But i would not get Asus or gigabyte.
 
But yea, Palit Gamerock is THE best GTX 1080 on the market right now. No arguing about that ^^
 
The MSI however has 3 years warranty, and a max power target of 291 Watt. Palit "only" 240 Watt. So the MSI might have a higher Overclocking potencial without worrying about Power Target.
So if you don't plan to overclock a LOT, take Palit or Gainward.

MSI
Performance wise no major difference
have heard the least amount of issues with their software and definitely best warranty service

MSI GeForce GTX 1080

The MSI one is the best but for something better get the Zotac GeForce GTX 1080 8GB AMP! Extreme Video Card  

The asus one has 2 connectors for fan that you can place on the case.

If you want to gear cooling towards GPU temps

Would say the Gigabyte is worst of these specific 3 in test I have seen. Asus is marginal better in performance then MSI, but the MSI seems to make noticable less sound compared to Asus. I find noise an important factor, so I lean towards the MSI.

idk but gigabyte cards seem to be poorly binned because im not the only one that there gigabyte g1 card overclocked +0 any higher it crashed 

Palit hands down. I had to specially order the palit from the UK to canada.
 
own a msi card too and the palit sends the msi card out the window in terms of noise and temp.

Palit is not a big thing here in NL, so can't tell you much about that. Allthough on the rare occasions I have seen one in tests it is overall perfoming good enough. For the 1000 series the out of box clockspeeds are indeed not crucial. The GPU boost always boost over specified settings unless you would have a crap cooler. So the best way to know is look at reviews. It is more depending on how well the cooler functions. Better cooled = higher boosting and steady performance lvl's.

If it does increase the response time at all, it'll be by such a miniscule amount (we're talking thousandths of a second here) that you will not even notice.
By the way, the difference you noticed in your monitor was very likely due to the jump from 60Hz to 144Hz, not from 2ms to 1ms. The average human is literally unable to discern a 1ms difference in anything.

nothing that you should be able to physically notice

The only thing suspect I've found was access to my account in April 3rd at 4:34pm from Internet Explorer. I don't use internet explorer, so I wonder. But this iAd thing started the day before, so I don't know if this is related.
 
Anyway, I've changed the password and used the gmail's "sign out all other web sessions" option. Let's see if this fixes the problem, if it's an unauthorized access issue.
 
Edit:
 
Thanks, Blebeckblebeck. I've deactivated that option now.

1a. Most games it probably can but it will have troubles in the more demanding games where you will have to drop down to med/high or drop specific settings.
1b. I don't know, wait for others to give you that answer.
1c. That's not true at all. The thing that that 120/144Hz monitor have TN panels which have less accurate color-reproduction and worse viewing angles but that's it. It's not tied to the refresh rate but to the type of panel.
1d. I also gamed on 2ms monitors but now on 6ms and honestly I only really noticed it in games like CS:S that have no camera acceleration whatsoever.
1e. It will cost about 1 fps on desktop and about 1-5 on youtube videos and such, the impact is minimal.
1f. Will recommend in a moment.
1g. Same as 1f
1h. I'm not an expert so I do not know which are the best. The ones I know are good are down below.
 
2a. Most newer games are compatible already, it's usually the older games that see a decrease in performance with SLI but those games 99.9% of the time don't need SLI to run on the highest settings at 60 fps.
2b. Yes, a 650W PSU does not give enough space for other devices/overclocks. I recommend getting a 750W PSU for NVidia SLI and 850W for AMD CF (EVGA G2 750/850W, Corsair RM750/850)
2c. Not same brand, they just have to be the same GPU so you can SLI with 1 ASUS 780 and 1 EVGA 780. The speed of the cards will be dictated by the primary card if I recall correctly.
2d. You can deactivate SLI via software. You can also remove the SLI bridge (which is done in seconds, it's that easy)
2e. The reference cooler is more suitable than the ACX Cooler for SLI (due to how it dissipates heat) that could be worth looking into. Also I do recommend utilizing all case fan options to keep everything cooled.
 
A few monitor suggestions (Note, I filtered for 24-27" monitor. If you don't mind 23" just say so but I was under the impression you wanted a 27" monitor):
 
http://pcpartpicker.com/part/asus-monitor-ve278q - 27" 1080p native, 2ms, TN panel, 60Hz
http://pcpartpicker.com/part/asus-monitor-vx279q - 27" 1080p native, 5ms, IPS panel, 60Hz
http://pcpartpicker.com/part/asus-monitor-pb278q - 27" 1440p native, 5ms, IPS panel, 60HZ
http://pcpartpicker.com/part/asus-monitor-vg278he - 27" 1080p native, 2ms, TN panel, 144Hz
http://pcpartpicker.com/part/asus-monitor-90lm00u0b01370 - 27" 1440p native, 1ms, TN panel, 144Hz - This is the only low response time 1440p monitor there is but it's damn expensive at $807,58