What is your desktop monitor set for programming?

I usually work with my 15" Macbook Pro, and sometimes at work with a external 21" 1080p.

Now I'm considering to go further. Options are:

1) Simple: 24" 1920 x 1080 at 60 Hz . ( AOC - ultraslim )

2) 21:9 UltraWide FHD (2560*1080)

3) Double set of 1) ( for vertical display programming, etc )

Budget is 100-300 ~ €/$/£

Do you only work on laptops?

How do you set your desktop environment?

Any experiences, preferences or suggestions on perfect set up?

Many thanks.

I have a Dell P2415Q 4K display (1080p retina) and my MacBook open next to it. Was thinking about getting another 4K display and closing the MacBook.

So I guess from your side, it's worthy to go wild and spend the money on a 4K?

Yep, I can't work on non-retina anymore. My eyes burn from all the blurriness.