(report link)foobar2000: An advanced audio player for the Windows platform. Some of the basic features include full unicode support, ReplayGain support and native support for several popular audio formats
(report link)Reed Kotler Music: Transkriber Learn-By-Ear Software - Slow the music down but keep the same pitch. These products are used by many top transcribing professionals.
(report link)Roni Music Amazing Slow Downer: The main product is the Amazing Slow Downer software, intended for musicians wanting to slow down music without changing the pitch. Amazing Slow Downer is available for Mac and Windows computers.