27″ iMac
In 2011 I moved from having a laptop as my main computer all the time back to having a true desktop computer, and for that I went with a 27″ iMac. That was pre-Retina, of course, but made a big difference. You can see a picture of this setup at my TMO workspaces article, which also details the standing desk I use.
In 2015, I moved to a Retina 5K 27″ iMac (4GHz Core i7, 512GB SSD) as soon as they became available on Apple’s refurb store. To this I added a 27″ Viewsonic VP2768-4k UHD “retina” screen and use that to this day.
But as soon as those 2019 iMacs hit Apple’s refurb store, I’m all over it!