Good music composition software
What I want is something that allows me to enter music on a stave, write and view multiple parts at once, playback with MIDI, and record as an audio file when I'm done.
Last time I looked at this, years ago, I used Cakewalk, which back then did what I wanted apart from being able to easily export to audio. Perhaps it's worth looking at again, though I must admit I don't remember the software with any real fondness. (To really date this -- my solution to the audio problem was to output from the sound card to a MiniDisc -- remember them? -- and then re-sample and record to MP3 from the disk.)
Back on Twitter, Orestis suggested Sibelius (warning: irritating noisy Flash site), which does everything I want and more... but costs almost £600. They have a "student" version which does everything bar the audio recording but is affordable. It's certainly got a good reputation, so probably worth giving a go, anyway.
njr suggested Lilypond, but that looks more like a way of printing scores from its own markup (though I may have the wrong end of the stick there). [Update: apparently it has a TeX-like input format, but prints scores and generates MIDI files from it. That sounds well worth investigating.]
Definitely more research to be done. In the meantime, I'll occupy myself with
my piano roll spreadsheet,
which can play back a tune using the .NET
Console.Beep function :-)