Premium 2m Gold Plated DVI-D to DVI-D Cable by Cable Mountain - £8.45

I added a graphics card (a cheap Radeon HD4550) to my computer specifically to be able to use a DVI output, and have just got around to purchasing a monitor with DVI-D input (Acer X243H 24").

This cable was easy to fit to both monitor and graphics card, although the screw pins were a bit fiddly (not really of consequence). Booted up system, and the resulting display is pin sharp and a noticable improvement over the analogue VGA connection.

If you have the option of DVI over VGA, you should use it.