Review of Aegissub powered by the Slant community.
Available on Mac, Windows, and *nix platforms
Ranked in these QuestionsQuestion Ranking
Pro Karaoke friendly
Aegissub was practically designed to make stylistic karaoke subtitles.
Pro Predefined shortcuts
Predefined shortcuts for navigating the waveform / timeline helps immensely in making quick work of setting timings for subtitles.