After listening to music through cheapish one-box systems for years, I finally wised up a month ago and bought a Rotel RA-04 amp, Marantz CD6002 CD player, B&W685 speakers, QED Silver Anniversary XT speaker cable, Cambridge Azur Reference interconnect, and Partington Ansa 60 speaker stands (much of this equipment on the strength of What Hi-Fi reviews). WOW - what a difference - it's rejuvenated my entire CD collection! I'm even enjoying those CDs I previously thought I wasn't that fussed about.
Anyway, I bought some squash balls yesterday, halved them, and put the halves under the feet of my CD player and amp (based on a tip I picked up somewhere on this forum - been lurking for a while but don't really know enough yet to make a worthwhile contribution...!). Now, I could be fooling myself, but I honestly believe this has made a genuine difference to sound quality - the music seems more 'taut' and clear. So, for any fellow junior hi-fi owners reading this, I can definitely recommend trying this as a cheap and easy way to improve your sound.