Since I am a choir director and often do new settings of music (or typeset music that was previously handwritten), I often need to typeset music. I have tried a few different programs for this, including Allegro (a subset of Finale), but I am most happy with Lilypond, which is now the only music engraving software I am using. Lilypond is also chant-friendly, and can do square-note notation (ala Sputnik Psalmochika for example), which eliminates some of the kludges done in Finale for chant. The above Essay discusses why, if you might want to consider using Lilypond. There is a bit of a learning curve, but once you have some templates in place, it is just as easy as anything else - perhaps more so. Since the basic input is text based, I can even start typeseting a piece on my PDA. And yes - it means that I now also do music engraving in vi :-).