Most people love the portability of their laptops, but find that the screen is not large enough or bright enough for use at home at or at their desks at work. Virtually all laptops support hooking up an external monitor which is a great solution for most people. Until recently, there were a couple of choices for external monitor technologies. CRT screens were very affordable, but were heavy and took up a ton of space on your desk. LCD screens were attractive and compact, but very expensive. In the last couple of years, CRTs have virtually disappeared and LCD screens are now very affordable because of improvements in the manufacturing technology and because so many are made and bought each year.
Now, the most important decision you have to make is about the size of the LCD. With few exceptions, the price of the monitor will increase with the size. Many different brands make LCD monitors, but the differences between the brands are less than you may think: only a small number of original manufacturers make the LCD itself, which is then resold under a variety of manufacturer's names. These days, a 20 inch screen is a good trade-off between cost and size. 24 inch and even 30 inch screens are available and increasingly common, but are much more expensive than the 20 inch versions which you can find on sale very affordably from a range of brands. Be sure that it can connect to your computer or you may require a VGA or DVI video adaptor. Some screens can also connect via HDMI.