The CRT is dead, with almost no monitor manufacturers continuing with conventional cathode ray tube models.

With their slim-line, sleek cases and flicker-free displays, LCDs now reign supreme, but they're certainly not all created equal.

How big should I go?

The good news is that size for size, compared with CRT monitors, LCD give you extra.

That's because, while both types of screen are measured on the diagonal into the corner, LCD monitors can display right to the edge.

For example, a 19-inch LCD has approximately the same working area as a 21-inch CRT conventional monitor, while also offering massive reductions in bulk and weight.

We all like to get the best value for money, so when buying a monitor it pays to go for the most mass-market option.

For regular aspect ratio screens, 19-inch is the most popular choice but, just as widescreen LCDs have taken over our living rooms for TV viewing, they've now got their not-so-beady eye on the desktop as well.

We'll look at all the pros and cons of widescreen monitor a little later but, for now, let's start with resolution.

Unlike CRT screens, LCDs are only truly sharp at their native resolution, where the horizontal and vertical pixel counts of the graphics card output exactly match the pixels on screen.

Regular 19-inch screens have a native resolution of 1280x1024 pixels, whereas super-sized, regular aspect ratio LCDs, such as 21-inch monitors, have a higher 1600x1200 pixel native resolution.

This level of resolution makes them more suitable for professional graphics and CAD/CAM work.

What inputs do I really need?

The vast majority of computer monitors come with a D-Sub video connector, which feeds from the analogue video output of the computer's graphics card.

However, analogue video is prone to interference or 'video noise' when displaying high frequency signals so an additional digital DVI input is preferable, especially for higher resolution monitors.

Other options for extending the capabilities of a monitor are the provision of S-Video, Composite Video and SCART sockets, for compatibility with a wide range of camcorders, digital cameras, set-top boxes and games consoles.

To make the most of the latest high-definition devices, such as up-market camcorders, Blu-Ray players and high-definition games consoles, you'll need an HDMI (High-Definition Multimedia Interface) port as well, which includes connections for audio as well as high-definition video.

What are the pros and cons of widescreen monitors?

The fastest growing area of popularity in LCD monitors is the widescreen, or 16:10 screen format. 19-inch (1440x900) and 20-inch (1680x1050) widescreen displays have largely dropped by the wayside, with 22-inch and 24-inch models currently being most popular and therefore best value.

The native resolution of a 22-inch widescreen is 1680x1050, the same as a 20-inch model, but the extra size makes text a little larger and more easily readable.

A 24-inch monitor ups the maximum resolution to an impressive 1920x1200 pixels.

One obvious advantage of widescreen monitors is that they're great for watching DVD movies on your PC, especially when combined with a good surround-sound speaker system, rather than relying on the normally tinny little speakers fitted to most LCD monitors.

However, the extra width of these displays also gives them an edge in productivity, as they're ideal for viewing multiple windows tiled vertically on the screen, enabling easy cutting and pasting between programs such as word processors and spreadsheets or web pages.

Bear in mind though, that a widescreen monitor will have significantly less height than a similarly sized screen with a conventional aspect ratio.

What's the best choice for digital photos and movies?

Colour rendition, brightness and contrast, as well as tonal separation (the ability of the screen to display subtle differences in greyscale steps) tend to be extremely good in the latest round of LCDs.