I think it depends what you’re after. I found that 1 big screen helps with the overview working on a sound project. But there are so many windows to open and close all the time, I like having those things I access semi-often on a second screen.
I tried having 2 side by side, but as driskel said, too much viewing width. I constantly had to move my head and move around to see what’s on the far left and right edges. Maybe that works for Nuage, that has specific things on each screen, but for kind of an “all purpose” screen I found it counter productive.
Right now I have 2x 27" screens. One is on top of the other, mounted on an arm. This way also my monitor speakers don’t have to be that far on the left and right side and the screens don’t attenuate the sound (my room is quite small).
A really long curved monitor might also be worth considering. This way you’d have a lot of content and timeline on your monitor and still space left for a TV above that.
But, I’d like to have some kind of 3rd screen just for communication. When I open mail or Skype, have those programs sitting only on that screen so it doesn’t get mixed up with my project work. I tried some stuff but the best solution I came up with is using a laptop for that. In game projects I have to work and communicate with so many different people from the team, that I had to have so many communication apps open, it covered everything. When alt tabbing, I had to press alt-tab so many times to find the right tool. So it’s really good having those apps on a separate computer. This way, the software also doesn’t distract you from work and all comms can be just stopped by closing the laptop’s lid while all my project stuff continues to work.
In order not to use a second mouse and keyboard, I use Symless Synergy. A tool that acts like a KVM switch, but in software. You move the mouse pointer out one edge of the monitor, it appears on the laptop. Works great for me.
If you’re looking for good screens, depending on size and resolution, I just read this article on good Mac screens. Of course those can also be connected to a PC. Apple’s Thunderbolt Display is dead: These are the best 4K & 5K displays for Mac - 9to5Mac
Maybe it helps.
How’s it usually done actually. To have the movie on a normal TV screen. Do you guys buy a normal TV for that and then have some kind of video card like the mentioned blackmagic? Or how does that work? For now I always had the video on the second (upper) monitor. Worked OK for reference.