Flatscreen displays use two distinct technology types: TN (twisted nematic) and IPS (in-plane switching). TN screens have been found in almost every LCD flatpanel and laptop screen for the past eight years. The liquid crystals are heated and twist round in response to current from a transistor. This mechanism polarises light in order to create colours and the illusion of movement. However, TN screens look best viewed straight on since that's where all the crystals are deliberately aligned.
You don't get such a good view if you look at whatever's onscreen from the side. If you have only a shallow view of the screen, you'll hardly be able to see any of the detail and lose almost all the colour. You will instead see mostly screen sheen.
IPS technology was developed to combat these two issues. The display is still fitted in an LCD panel, but the liquid crystals that make up the display do not twist away, so the way light is polarised through them is more consistent. It's considerably more expensive to produce an IPS panel, since two transistors are required for each crystal. However, you may find the difference in screen quality worth paying for.
An onscreen image is created by turning on and off individual pixels to simulate nuances of colour. This is done very quickly in order to simulate fast-flowing action. It's therefore important you consider how reactive the flatpanel display is. This is known as the response rate. If you want to play fast-paced games, a response rate of less than 5 milliseconds is desirable. The fastest screens we've seen have response rates of 2ms (two milliseconds). However, for watching videos and for general business and entertainment use, a screen with a response rate in single figures is fine.
Another important determining factor here is the connection between your PC or laptop and the screen. If both the content and the connector are digital (DVI) or HDMI, you'll have the best combination of original image or video quality and communication between the source and the display. Most PCs these days have both a DVI (digital visual interface) and a VGA (video graphics array) port. The VGA port is analog and is a legacy port used by some projectors and older monitor types. Given the choice, you should connect your screen to your PC via DVI. However, if you wish to connect two screens at once, one of them may need to use the VGA port. Your graphics card may have an additional DVI connection you can use, however.
If you want to connect your new flatpanel screen to your laptop and enjoy the larger display, you should find a DVI port. You may be lucky enough to have an HDMI connection too. In this case you'll probably be able to play whatever's on your laptop to the HD TV in your lounge too.