Everything you need to know if you are buying a Blu-ray Disc drive, or a Blu-ray Disc player.

For the complete Blu-ray set-up, you'll want a Blu-ray Disc drive with which to create Blu-ray Discs, and a Blu-ray player with which to enjoy their HD and 3D contents - unless you are happy watching Blu-ray content on your PC. For more advice, visit Digital Home Advisor.

Let's start with the basics. Why would you want a Blu-ray Disc drive or -player? One word: space. A single Blu-ray Disc holds the equivalent of 35 CDs or five DVDs. A Blu-ray might look like a DVD, but because it utilises a shorter wavelength and a narrower laser beam spot, it can hold greater capacity. The laser's blue, but the way, but you guessed that.

Even this wouldn't be at all interesting, storage capacities being what they are, but Blu-ray is the storage methodology of choice for HD and 3D content. The extra detail takes up more virtual storage, the Blu-ray disc takes no more physical space.

When purchasing a Blu-ray Disc drive for your PC, there are several factors to consider. Perhaps the most banal, but arguably the most important, is whether to get an internal drive that you fit into your PC's chassis, or an external drive you simply plug in to any available port. External drives are easier to install, portable, and can be shared between computers, but they will cost you considerably more than internal models, and may not be as quick.

If you go for an internal drive, you must ensure you have a slot for it in your PC, as well as the physical space to fit it, and the expertise to do so. Most internal drives now use a SATA interface, so check that you've got a compatible port. If you have a laptop and it doesn't already have a Blu-ray drive, you are unlikely to be able to fit one.

Next consider what DVD formats you to which you wish to be able to read and write. There's a lot. A LOT. To handle the bewildering array of DVD recording and playback formats, we recommend buying an optical drive that supports as many as possible. Look for labels such as LG and NEC's SuperMulti or Lite-On's Super All Write.

Don't obsess about writing speeds. You should be able to get 16-speed DVD writing, but it's not worth paying more to save seconds - not least because the same information will write to a Blu-ray disc in a fraction of the time it will take to burn to DVD. it's worth remembering that you need to be able to purchase the media in order to enjoy maximum write speeds. Six-/eight-speed BD-R (Blu-ray Disc writable) capabilities are the basic standard, but bear in mind that even six-speed BD-R media is still rare.

See also: Group test: What's the best Blu-ray writer?

You may, of course, be happy watching Blu-ray content only on your PC, but if you wish to enjoy HD content from Blu-ray Discs on your TV, you need a set-top player. You'll need an HDMI cable to connect Blu-player to HD TV. This will deliver high-quality, high-definition content, but don't be upsold. An HDMI cable is an HDMI cable, regardless of how much it costs.

Features to look out for on Blu-ray players include the ability to record TV, internet connectivity and BD Live. The former will be useful if you don't have a PVR (Sky+ box or similar), or you want only one set-top box. The latter two combine to ovver extra content via the web. One of the best Blu-ray players is the PlayStation 3, simply because it adds so much extra functionality to the simple function of playing Blu-ray discs.

Your Blu-ray player should have the ability to play existing DVDs, and will even upscale them to make them look better - although beware of false promises in this area.

See also: Group test: what's the best Blu-ray player?