Stereophile is reporting a huge flaw in iTunes 7.5 for Mac OS X. This came up as part of John Atkinson's January 2008 review of the Benchmark DAC1 USB. John worked with Benchmark Media Systems and Benchmark concluded iTunes 7.5 is flawed. Here is a snippet from Stereophile's website.
"Director of [Benchmark] engineering John Siau wrote, "We have discovered a very serious flaw in iTunes 7.5...[specifically] in the area of 16-bit truncation and/or operating system based sample-rate conversion…. Fortunately the truncation and sample rate conversion problems can be avoided in both Apple and Windows systems. Unfortunately, the iTunes 7.5 bug makes iTunes unsuitable for playback of 44.1kHz CD material. We hope that this bug will be fixed in the near future. There are several players that work flawlessly. Unfortunately, iTunes is no longer one of them! We will be reporting the media player bugs and workarounds on our computer audio wiki pages."
UPDATE : iTunes 7.4.2 for Mac OS X available if you need to downgrade.
UPDATE II: It is my understanding that Apple will be updating iTunes before the end of the year and possible the week of December 9th, 2007. This "should" resolve the current issues.
Here is a link to the full article.