Resolution: This is the big one you've probably heard of, and a higher resolution is generally better, but it's also worth considering the size of the monitor you're getting. The bigger the monitor, the more it will benefit from higher resolutions. That will allow you to have app windows that take up less space but are still legible. Refresh rate: This refers to how many times the display can refresh the picture per second, measured in hertz (or Hz). A higher refresh rate makes the action in games look smoother because you're seeing more information.

Samsung's 24-inch 390 Series monitor, is the best computer monitor you can buy in this price range. The C24F390 wins the nod thanks to its image quality, which clearly beats most monitors in its class. Its advantage comes thanks to the contrast ratio of its Vertical Alignment display panel. This monitor can display deep, inky black levels in scenes where most budget monitors only show a hazy, disappointing gray. Yet it's also much brighter than competitors we tested in everyday use. You might not notice the C24F390's advantage when editing a spreadsheet, but it's obvious in movies and games, which look vibrant and crisp.

I have just switched to a Windows desktop computer and need to get a good monitor – about 21 inches and under £200. Do you have any advice? There are two ways to pick a monitor, and it's worth using both approaches. The first is to go into a shop and see which one looks best. It's much easier to compare screens side by side.