The Mary Stallings "Fine and Mellow," mentioned above, is a terrific sounding album from a small label, Clarity, that specialized in ultra high quality recordings. I have that album from Clarity that came with two discs, each having only one side pressed on them. Another Clarity record I use to demonstrate great sound is Claudia Gomez "Salamandra."
Clarity also made really good CDs. One of the CD's containing Stravinsky's "Rite of Spring" has a warning about its extreme dynamic range--if you set your volume level too high for the extremely soft beginning, you could damage your speakers when the loudest passages kick in.

