One Large Monitor
One trend is to move to the single large monitor. Resolution at 4k is great enough that you can easily fit two or more documents on screen at once. You don’t have to turn to see different monitors, and there are no screen edges for a seamless viewing experience.
Current recommendation: Philips BDM4350UC 43-Inch
One Extra Wide Monitor
A newer option is the extra wide monitor. It takes on a similar role to the dual monitors without the bezel. When I was looking previously, the amount of screen real estate you were able to get for the price just didn’t seem worth the possible improved user experience. The prices have come down, so perhaps it’s worth checking out.
Current recommendation: LG 34UC80-B 34-Inch
Two Monitors
The two side by side monitors will still provide great screen real estate without the added cost of a larger display. These displays are becoming closer in price, but if you only wanted to add one monitor, or you need a monitor in portrait mode, this is a great choice.
Current recommendation: Dell U2415 24-Inch
Latest Version of My Monitor
I purchased the 4k Samsung U28E590D 28-Inch for $379.99 and $346.84 a couple of years ago. They work great still, but they seem to have been surpassed by newer versions and the decreases in price for the alternative display methods. This monitor is large enough that depending on your work style you may be able to get away with having only one of them, but they aren’t so expensive or large that running them side by side would be out of the question. Here’s the latest version of mine: Samsung LU28E570Ds 28-Inch