VLC Media Player - VLC is a free and open source cross-platform multimedia player and framework.
WinDirStat - WinDirStat is a disk usage statistics viewer and cleanup tool, inspired by KDirStat.
foobar2000 - An advanced freeware audio player for the Windows platform.
WizTree - WizTree quickly finds the files and folders using the most space on your hard drive. It scans the MFT (Master File Table) instead of crawling the entire disk which makes it very fast.
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.
TreeSize - TreeSize tells you where precious disk space has gone to.