There was a thread on this a while back, the need for opensource or
free/minimal cost alternatives to Sibelius and such on Linux.
One can run Finale Notepad or various lower cost upgrades using Wine and this
may be the best alternative if one can get the MIDI and printing working this
way.
For lack of a handy staffbook--and it is easier to simply grab a staffbook, a
extra fine pen and a typex stick--I tried what I have on my Debian Sid box:
Scoring:
Notedit--KDE's scoring program will get the job done. Most functionality is
there. Chord entry is very awkward and the ui needs more toolbar items. But
it works and will export to most everything needed including abc which opens
the door to many Windows and Linux programs that can print score, Lilypond,
MusicTex and MusicML.
Canorus--successor to Notedit. Too early for this one.
Denemo--GUI for Lilypond. Too early for this one as well. Nice start but had
to go back to Notedit to continue.
Musescore/mscore--new boy on the block. Coming along nicely and will soon be
the best around. Still work to be done, text field editing is nigh-impossible
but this is the alternative to Finale and Sibelius to watch. Imported MusicML
from Noteedit.
MIDI keyboard to any of these is precarious at best.
For printing (engraving when doing music):
Lilypond--works well with its peculiarities. Not enough control of formatting
when exporting from noteedit, et al. Denemo not ready so need to know its
markup language to really use it well. It is supposed to be the standard.
MusixTex--works nearly as well as Lilypond but does not handle UTF8, foreign
characters out of the box.
Musescore--one when sets the formatting parameters (not defaulted properly)
produces very nice results. Its scoring is WYSIWYG once the formatting params
are set up. Again, the one to watch.