I would use only a recording made with a minimalistic approach, as far as microphones are concerned, and a natural room ambiance - if this sounds great, everything else will, or simply reveal the limitations of other recording procedures.
Art Pepper Meets The Rhythm Section was the first to come to my mind, too - those guys sound like they are right in front of you.
Cliffors Jordan's live CD on Mapleshade is good for testing.
The SACD of the Cal Tjader with Stan Getz on Fantasy - vibes are good, if they sound crystal clear, it's all right.
I'd never use an ECM CD - too much digital trickery involved, they never sound natural.
For classical I would take a good harpsichord recording - those overtones are the ultimate sound test!