Suggestion for dual monitor setup.

Hi, I'm planning to build a new semi-high end gaming pc with the latest 8700K coffee lake and Asus 1080 graphics card. I have all the pc parts decided already..

I just need some advice on my dual monitor setup. 1 of the monitor will be the main screen where I do my main work and gaming (so gsync and all the expensive features should be on the main screen), while the other monitor will be a secondary monitor for things like Youtube, Discord or my ex's photo (so don't need gsync or high refresh rate, etc).

Preferably both should be the same size (I'm looking at 27"? idk) unless you guys have other suggestion. My budget is <500 bucks for both screens.

Pls do advice which monitors best fit my setup! Durability is the most important to me, I plan to use them for >5 years. My current rig is 7 years old haha