It is easy to forget about your the display when making a laptop comparison, but you should always consider it before buying. The display is what you'll be staring at for as long as you use the laptop, so it should be a good one.
Most displays are very glossy. This makes colors appear more vivid and also makes the laptop appear more attractive when not in use (i.e. when it is in a store). However, glossy displays are hard to use outdoors and in brightly lit rooms. Matte displays provide less attractive visuals, but they're don't create distracting reflections. Matte displays are rare - you'll usually have to buy a business-oriented laptop like a Lenovo Thinkpad if you want one.
The display resolution is also important. The layman often assumes a larger display will be able to display more information, but that isn't the case. It is the resolution - the number of pixels on the screen - that makes it possible to display more information. If you increase a display's size, but don't increase the resolution, you'll simply display the same amount of information at a larger size.
The most common resolution today is 1366 x 768. This is fine for laptops with a display size of 14 inches or smaller, but you'll also find this on many 15 inch laptops. Laptops of that size are often better with a higher resolution, such as 1600 x 900, but not all large laptops give you that option.