The added resolution of DVD-A and SACD is also imprtant for older analog recordings because there is more of the recording on the disc. So when you hear a guitar note, you not only hear the strings, but also the fingers sliding on the strings. But again, I would recommend reading reviews of SACD's and DVD-Audios before buying them because they can be poorly mastered or mixed.

One site I enjoy is www.highfidelityreview.com