VArranger - vArranger is a PC arranger software, playing Yamaha, Roland and Ketron styles in realtime !
NtEd - Music Score Notation editor.
JJazzLab - Fed up with boring backing tracks ? Try JJazzLab!
music21 - Music21 is a Python-based toolkit for computer-aided musicology.
Band-in-a-Box - Band-in-a-Box is so easy to use!
Sibelius - Sibelius is a virtual score creation tool which allows composers to easily create new piano scores, developed by Avid.