What is the best resolution for World of Warcraft

The best resolution for World of Warcraft would depend on the users hardware. If the user got a screen and a computer capable of running a high resolution the most common is to put the application to it's highest resolution possible. So in short, the highest resolution you can use is the best. But if you experience problems with the game performance such as drops in the average frames per second, you could consider using a lower resolution as that would lower the stress on your computer.