The last time we sat down to write a guide to audio-related purchases for your PC, the world was a very different place. Back then, it was still quite common for a PC to have an individual sound card in the box. Now? Pretty much any motherboard you buy - yup, even those for under £30 - will have at least 5.1 audio support built into the board. The upshot is that you'll be able to plug your speakers into your computer and get quality audio output, without the need for a separate sound board.

And truth be told, that's going to be ample for a heavy proportion of the PC userbase. Let's face it, the majority of us are just looking for audio of a good standard with the minimum of fuss, and that's just what on-motherboard sound solutions offer.

But is there any need at all for a separate sound card inside your PC? Actually, yes, if you fit into one of a couple of different camps. We'll take audio professionals as a given, although we'll be touching on a couple of options there shortly. But performance gamers may want to take note too.

As with anything built onto the motherboard, on-board audio does mean your computer takes a slight performance hit. Think about it; when it comes to graphics, a separate card is pretty much taken for granted, as there's a lot of work to be done there that's best handled by a separate component.

Anyone who's used on-board graphics solutions for anything other than the basics will be perfectly aware of the performance hit the overall system takes as a result. After all, the motherboard has a lot of work to process, and any resources it attributes to graphics aren't being used elsewhere.

And the same applies - to a lesser extent, granted - in sound. If the motherboard is decoding and outputting the audio, then it's using a degree of centralised system resources. For maximum performance, a separate sound card will leave those centralised resources to concentrate on key tasks, and so the performance of the system overall will improve. We're only talking a marginal amount, but it's generally gamers who look for any kind of boost they can get.

Kings of the internal sound card are still Creative Labs, although it's fair to say that their business is far less reliant on them these days (they've become more of a digital music device specialist, if anything). Their top-of-the-range solutions are the X-Fi products, which offer a staggering array of options.

They're available in different flavours too, from the top of the range X-Fi that comes with a breakout box to hook up lots of connections, through to the straightforward entry-level version which sells for about £80 as this guide is being written.

These are the high end cards of the sound card market (and will interest those aforementioned audio pros), and you really get what you pay for, with phenomenally strong audio reproduction, although clearly you need to hook up to some equally good speakers to get the best out of them. We'll come to those later, though.

Next down the line, and a product that still excels, is the Audigy 2 line. These have now dropped to a price point that makes them attractive as a more casual buy, but they certainly shouldn't be sniffed at. Only a year ago these were top of the range, and with sound card technology moving at a far slower pace than other areas of computing, an Audigy 2 will be a top quality sound solution for some years to come. Look around the regular e-tailers and auction houses and it shouldn't be too hard to pick up a good deal. The same applies to Terratec's Aureon range.

At the entry level, there are numerous manufacturers who will sell you a relatively bog-standard sound card, and in most cases this will still offer an added advantage to your PC. The likes of Trust and Philips offer sub-£25 cards for instance, although if it were our money, we'd still prefer to go in the direction of Terratec or Creative.

It's perhaps an old cliché, but its relevance shows little sign of subsiding: you get what you pay for. A more expensive card is likely to have a more favourable signal-to-noise ratio, added connectors for the likes of SP/DIF, breakout boxes and support for up to 7.1 surround. Even in the mid-range now - and we're only talking around £50 - there are some superb audio solutions available that should offer at least 6.1 output as standard.

Incidentally, if you're not the type to open up your PC and install a new card, then there are external sound devices that do the same job. There's a slight performance hit, naturally, and they also tend to be more expensive, but for around £40, you can still pick up an able and useful solution that should hold particular interest for laptop users who can't physically install a dedicated sound device otherwise.

A good sound device, though, is only as good as the speakers it's attached to, and that's an adage that holds true in computing as well. And the trick here is to consider the quality of your sound card when buying your speakers. After all, what's the point of shelling out for a top of the range 7.1 surround sound speaker set up if your computer is only outputting 5.1 channels from a sound chip that's built into the motherboard?

On the bottom rung of the ladder are entry level speakers that should only be used for occasional audio output. Trust's USB-powered SP-2850l, for instance, don't even require a power connection, but the proof of the pudding is in the limited - although probably better than you thought - output they produce. Generally in the sub-£30 bracket you're limited to stereo speakers of variable, although usually effective, quality.

But as soon as you find yourself spending £30-£40, you can find some very able solutions. For the majority of users, a 2.1 speaker set is going to be more than ample, and quality units from names such as Altec Lansing, Creative and Philips pop up in this price bracket. You'll also hit the low end of the 5.1 speaker market in this price range, but we'd recommend you avoid the budget products here due to the limit output they're capable of. If you're going to bother with 5.1, then you may as well have something meaty to do it with.

You don't have to spend much more, though. Quality budget 5.1 set-ups, such as the Logitech X-530 or Creative Inspire T6060 were bordering the £50 mark at the end of 2005, while Altec Lansing's equally useful VS3151R throws in a remote control too in a package that comes in just north of £60. 7.1 solutions start at around £70, although again, the rule of thumb applies; the more you spend, the more performance you're likely to get.

One note of caution. Always consider the size of the room your speakers will be located in. If it's a small office, with a relatively tight soundstage, then a set-up with relatively low output will suffice. The bigger the room, the larger the soundstage (effectively the physical space you're looking to fill with sound), the higher the output you'll require. Watch out too for packaging that doesn't state the output per speaker. Certain manufacturers have a habit of promoting the combined total output, rather than breaking it down.

One development worth keeping an eye on over the coming months is wireless speakers. As this guide was being prepared, one of the very first sets of wireless computer speakers hit the market, in the shape of Saitek's A-250. We expect widespread expansion of the wireless speakers market, although we don't expect them to be without teething problems. This is effectively first generation technology we'll see until the back half of 2006, and while we're confident that even the early wireless speaker packages will have their merits, if it was our money on the line we'd be playing a game of wait and see for the time being.

Hopefully this has given you some pointers to get going. Naturally, we also recommend that you check out plenty of reviews. Coincidentally, we have a few for you here.