Apple has changed the preferences in iTunes 8. Several readers have complained that they cannot find the import settings anymore.
To make sure you import higher-quality MP3s (or AAC, Lossless, etc.), go to iTunes: Preferences: General Tab: Import Settings.
The default is the old-fashioned and lower-quality 128 kbps MP3. We recommend changing it to the higher-quality “AAC 320 kbps” or to “Apple Lossless” (these lossless files will be much larger though, but sound as good as the original AIFF). We prefer the AAC 320 kbps setting for the combination of good sound quality and manageable file size.
While you are at it, go to the pull-down menu of Window: Equalizer. Turn on the equalizer and choose the Jazz setting. Best sound for our Klipsch subwoofer system!