[brimstone]

The idea that increased resolution and sampling rate over standard CD-quality gives an audible difference is not supported by double-blind listening tests (except at very elevated levels). The most recent and comprehensive study in this subject was published this September in Journal of the Audio Engineering Society (1). When DVD-A discs (or vinyls) sound better than CD:s it's most likely because the sound engineers did a better job.

(1) E. B Mayer and D. R. Moran, "Audibility of a CD-Standard A/D/A Loop Inserted to High-Resolution Audio Playback", J. Audio Eng. Soc., Vol. 55, No. 9 (September 2007)
(It's not available on the internet for free but i could probably email it if anyone is interested)