I have: Cambridge Audio S70 speakers & Cambridge Audio azur 540A amplifier connected via phono to an M-Audio Fast Track USB external sound card, which is connected via USB to my computer. I would say that my amplifier and speakers are sufficiently 'warn-in', and I am using high-quality cables. The 'sample rate and bit depth' properties for the driver, on my computer, are set to the highest settings - '2 channel, 24bit, 44100 Hz (Studio quality)'. For practical reasons, I play most of my music through Spotify Unlimited, which streams (having emailed Spotify for official reports) "99.9%" of their music "at [and not just 'up to'] 320kbps", mp3. I understand that these files are compressed and will be of a lower quality than CD's for example. My speakers are located about 3-4ft apart from each other, at a slight inward angle. I am sat just 1-2ft in front of my speakers, and my reciever is located directly in front of my, under my computer monitor. My room is small-to-average.
http://i41.tinypic.com/33w30h3.jpg
To put things into some context, I bought the Azur 540a with 340C for £120. They had been used only once and only with headphones.