The web site for National Public Radio makes extensive use of streaming audio to make its archived broadcasts available to the public. A limiting factor for all audio and video transmissions is bandwidth. As a result, streaming audio files must be compressed by a factor of 50 to 100 before they can be streamed on the web. Compressing audio files, however, degrades the quality of the audio. An AIFF digital audio file might sound great when downloaded in its original form but will likely be less satisfying when converted to a streaming audio file.
Today streaming audio is an excellent way to deliver speech-based audio.
Music, however, is less successful as streaming audio. This increase in bandwidth is one element of the much-heralded convergence of consumer electronics, traditional broadcast, and computer technology expected within the next decade. I recommend MasterTracks Pro or Vision for the average musician or multimedia hobbyist. For professionals who demand a comprehensive feature set, I recommend Performer for Macintosh or Cakewalk for Windows.