Mixxx is Free DJ software that gives you everything you need
Midiexplorer is designed to explore a large collection of midi files
Ballroom Music Player
audio sequencer
A music tracker software for Windows.
Simple visual and acoustic metronome with bar-based song part tracking
Your Hardcore Loop Machine for Windows, Linux and OS X.
Loop based software with jack transport, record and midi controllable
VST instrument playing mp3 files
Calculate the BPM of a song!
MIDI and/or Custom WAV Metronome for Windows and Windows Mobile
Simple free metronome for training musicians