FL Studio is a full-featured, open architecture, music production environment for audio recording, composing, sequencing and mixing, and the creation of professional quality music. It is a shareware sequencing application that's comprehensive, reliable, powerful, professional, light on system resources and efficient.
Here are some screenshots to illustrate the features and user interface of this application:
Aegisub
Cakewalk
ocenaudio
Sofeh Music Studio
HitFilm Express