include (or link) a full GM soundfont
Obviously, including a full GM soundfont would significantly increase the size of the package but it would also do wonders for the user friendliness of musescore- especially to MIDI noobs. I've heard that linking to QT 4.5 significantly reduces the size of the Windows QT4 library footprint so if thats the case then it might balance it out a bit. Musescore in only small at 14MB now anyway.
If it would be too much extra overhead on the package size then we need to link to some (or at least a) freely available GM soundfont under the 'Links' page.