My first choice would be a CD based system. In my experience it's easier to get better performance from that format than it is with vinyl or streaming at this kind of price point. Second, everything changes if you start to include second-hand, and I think the question then becomes unanswerable because there are far too many options. For the sake of clarity, brevity and sanity (

) in this exercise then the choices should be restricted to new product only.
Next, we need to define what "sound system" means. Personally it's a 2 channel Hi-Fi but others might be thinking along the lines of a surround system. If so then IMO that's not a system for "primarily listening to music". I would also include here the condition that any system incapable of showing up why the typical freebie phono cables and bell wire is inadequate really shouldn't be included. Likewise anyone who hasn't yet heard that kind of difference in a proper budget Hi-Fi system probably hasn't the right kind of experience to make suggestions about what to buy. That might sound harsh but in all honesty would any of us here be happy taking a recommendation of what to order at a really good quality restaurant from a dining companion whose only experience is comparing Maccies versus BK versus KFC?
A good music system then won't come from Currys/PC World, and I wouldn't expect it to come from a large department store either. It might not even come from an independent electrical retailer the kind of which you might find under the Euronics umbrella unless they have specialist knowledge and an equipment selection that is more specialised than the TV/AV brands. What's required is a dealer that carries a range of pure 2 channel Hi-Fi brands within their product ranges, and a place with at least one dedicated listening room along with the knowledge and experience to demonstrate effective product choices. In short this is either a specialist Hi-Fi dealer or a company with a dedicated Hi-Fi department. Companies such as Richers, Audio-T, Sevenoaks come in at the shallow end of that pond. The real players though are the sort of companies you find that stock Rega, Roksan, Creek, Avid, Arcam, Teac, and similar as their bread & butter ranges.
As a rough short list then I'd audition something along the lines of a Marantz CD6005 CD player (£300), Onkyo 9010 amp (£180), Monitor Audio Bronze 2 speakers (£249). The remaining budget would be allocated to stands and cables. Decent budget speaker stands are a must as far as I am concerned. Allow £50-£90 in the budget for them. For interconnects then a pair of Chord Crimson @ £65 would be appropriate. (I have Chord Chrysalis in between my CD player and AV amp and it's still easy to tell the difference between them and a set of the freebie phono leads.) Speaker cable, something 79 strand and of a decent gauge appropriate to the length will do fine; either a 1.5mm or 2.5mm CSA pure copper. Personally I think Van Damme Blue is a good basic choice, but if we are going for pure Hi-Fi rather than AV then it's worth a listen to Chord Rumour 2 as long as long as the cost doesn't top more than £100 for the length required.
The above would be a decent starting point for auditioning other gear, but as a system in itself it should do everything right in a musical sense to get the most from CD.
Originally Posted by Winston_1:
“As for RCA cables the cables supplied with sources are generally good enough. You don't think manufacturers of high end equipment would spoil their product with crappy cables surely?”
It's not so much about sound as just being able to use the gear straight out of the box after purchase. But I think one has to consider the sort of gear where cables are thrown in free. It's the type of product that's likely to be bought without a demo, so a take-away product if you like. I think that means a different set of expectations compared to something where the dealer service level is much more complete.
I wouldn't take the presence of freebie cables in the box as an indicator of a product's quality per se because it could come from the culture of the company. For example, Sony sells (or at least used to sell) CD players from under £100 to over £2000. Each would come with free leads because "that's the way they do it". Rega sells CD players from £500 and above. None come with freebie leads because they expect the dealer to demonstrate a range of compatible 3rd party accessories in order to build a complete solution that gets the best from product. It's different approaches.