Just a quick comment regarding Quads & Amplification. I have Quad 21Ls myself and will be powering them with an Monarchy SM-70 within the next few months, moving away from a NAD C350.
Regarding SOURCES and the Quad becomes a bit more interesting. You can look through my post history to find my Player roundup (Rega Planet 2000, Arcam 73t, Cary 308, Creek CD50mkI, Roksan Kandy MkIII, and the Cambridge Audio Azur 640c).
Cary and the Creek were the best of the bunch, Arcam third (more similar to the Cary than the Creek) - and the Arcam had real issues with rhythm regarding higher frequencies. I know that sounds vague but the roundup describes it pretty well and the track I was using to examine the high end had a lot of synth / wind chimes and it was very clear to everyone in the room that the Arcam wasn't pulling the detail nor the proper placement nor the proper order (and speed etc hence rhythm comment). Either way read the more detailed post in my history.
If you can do try the new Creek CD50 mkII its supposed to be about as good as the old one but more tolerant of copy protected CDs. The Cary is a great player as well, with more slam than the Creek so it really comes down to 'taste'.
Amplification my tests have been fairly limited but I have thrown the Sophia Baby (10wpc Tube Amp) at it and was quite impressed - Dynamics were still sufficient at normal to slightly louder listening levels. The Monarchy I'm going to is quite wonderful and I simply love its tone, and PRAT. 25wpc x 2 Class A.
Either way there is a lot of flexibility with regards to amplification in these speakers. I've heard other people say good things about Tripath amps (eg Bel Canto) being used with the Quad L-Series, McCormack, Monarchy, and Tubes.
The Quads are very detailed and can easily be fatiguing if you have poor upstream equipment (a problem my setup had for quite some time until a poorer source & speaker cable were taken out of the system). I find the Quads perfer Copper based interconnect/speaker wire to that of Silver Plated Copper, or Pure Silver. That's a personal preference though.
Hope this helps, if you have any more specific questions please feel free to e-mail me.
Nathan Klassen