most of the freeware/shareware is good for lead sheets, but doesn't offer all of the options necessary to do an orchestral or band score--stuff like the capacity to do the conductors score, with multiple staves, and the ability to extract parts in the appropriate keys, as well as the ability to customize different aspects of the score, and to create large documents all costs extra

Just to bang on again about "Melody Assistant" (US$20)and "Harmony Assistant" (US$70). Both of these can be used to create conductors score with multiple staves, extract parts in appropriate keys and create large documents and both have some ability to customize different aspects of the score. The biggest difference between them as far as I am concerned is that HA gives MUCH better layout of both the individual bars and the score as a whole. Of course, whether either of them can do a specific customisation you might wish is difficult to answer. For example, there is no ability to analyse a MIDI file and identify possible repeated sections, and I have not found it terribly easy to identify these 'by eye' and cut and paste the sections into a tidied-up score. Nor, when you extract parts, does there seem to be a convenient way of representing that fact that such and such an instrument has 100 bars rest.

Both these tools can read and write ABC. However, be aware that ABC is not as standard a standard as you might wish and there are some aspects, such as triplets, that these tools produce in a form that meets the standard but that other ABC processors do not recognise. Other areas, such as mutilple voices, are still unsettled.

Here's a brief description of how I manage (a proportion) of my songs. With my work over at folkinfo, I normally prepare the score in HA, where I can visually and audibly check the entered score against the original printed source. Although the system comes with a default keyboard mapping to assist with entering notes, for me the quickest way is to use a modified mapping so that my left hand selects note/rest duration (keys 1-5 and the odd key to the left of '1' for dotted and double-dotted notes) and the right hand to move the mouse onto the relevant stave line. Once I have entered the melody I then export it to ABC and run it through a little uility Jon Freeman produced which passes it into ABC2MIDI and one of the ABC-to-PDF processors. I do this because of the triplet issue and because way back in the early days of the site I pushed for laying the score out to suit singers rather than instrumentalists, so the scores are biased towards sensible breaks in the lyrics rather than the more standard breaks on bar lines. As HA breaks on bar lines I often have a few tweaks to move a note or two from one ABC line to another. Once that's been done I type up the rest of the lyrics and post them to the site.

I could of course simply use ABC throughout, and typing C/ is pretty quick. But I found the checking cycle was faster this way, especially with multiple staves. For example, with Diadem I have so far spent 39 minutes in HA. That includes entering the stuff, reviewing it and playing it several times, some one which were after the tune was entered. Be aware that the presentation you see in that link is the one from the ABC-to-PDF tool, not HA itself.