Spotify - Map shows when two people play same song at same time
VLC Media Player - VLC is a free and open source cross-platform multimedia player and framework.
SOUNDS - Discover music with friends
foobar2000 - An advanced freeware audio player for the Windows platform.
Songlink - Share music with anyone.
Winamp - Winamp is a media player that allows users to play multiple-file formats, arrange media in a varied file-management system, and play unique media with AAC encoding.