The Audigy - Creative's latest sound chip model.
Though AC97 codecs support multiple sound channels and high sampling rates, and additionally have excellent compatibility due to support for Microsoft's Windows Driver Model, they are still lacking in quality. Users that primarily want to hear application or Windows sounds and listen to a MP3 file or CD from time to time won't benefit from an additional sound board.
But those who like to listen to orchestral music or similar types of music at high volume will appreciate sound hardware with a high signal-to-noise ratio. In addition, all advanced sound boards come with support for at least four speakers - the Maya 7.1 Gold actually supports eight (seven speakers plus subwoofer). Both factors will noticeably increase the sound experience.
Dedicated sound boards also come with several line-in and line-out ports, either analog or digital (coax or optical), ensuring perfect connectivity to other sound hardware (CD or Minidisc player, DVD player) - yet the main application for line inputs might be simple music recording. Thanks to digital audio extraction software today, you don't need to attach a CD player to your sound card line-in in order to record music. Instead, you can simply "grab" audio data to wave files on your hard drive without any loss of quality.
Many people tend to think that dedicated sound cards put less of a burden on the CPU, which is simply not true. Sophisticated sound effects and multi-channel output definitely consume more performance. And when simple stereo output is required, the differences are too insignificant to be worth mentioning.