Used to use just one 19" monitor for web design work and web browsing. Then I bought a 24" Dell and decided to use the 19" as a secondary monitor and it was like a whole new world opened up. I'd sometimes turn the 19" monitor on its side and have my code running vertical, in order to see more lines of code.

The extra monitor also comes in handy when I watch sports. I'll have the TV on the game and then Twitter or Discord up on one monitor and then ESPN's GameCast on another.

Best PC decision since buying a SSD.