Asus Rog Swift PG278Q -g-sync, 144Hz, 1440p. 2014 model. Running 5K scaled resolution via Nvidia driver setting DSR factor x4.00 setting.
If you are a fps gamer I would go for a monitor with the lowest possible input lag. 1 - 4ms and 120-165Hz
60Hz is like console gaming on a TV = very slow mouse feeling.
Depends of your pc use or what you are gaming
Building a gaming pc is like building a Hi-Fi setup. Every hardware piece in the chain ( mouse -> ... -> monitor ) should match each other in quality or the best parts might be a waste of money.
On youtube there is tons of gaming benchmark fps tests comparing cpu´s, ram etc.