For a christmas present I’ve decided to compose a short piano piece for someone… but as I am not longer in school studying music, I don’t have access to cubase or sibelius there… Ideally I just need something to write down the music, like Rosegarden for linux, but unfortunately I don’t have the harddrive space to install a linux distro. Any suggestions? 
hopefully there’s something here:
Your best option is that scripting based one I think, because Finale Notepad is terrible.
I’m thinking of going into college for music composition. Is that what you were doing?
Thanks guys, lilypond looks cool, reminds me of LaTeX. No I’m not studying music in college, I already study computer science. Purely a hobbyist, I play flute and piano and do composition for fun.
You can also see if you could get hold of Agnula DeMudi
There is a live version so that you can boot the entire distro from CD without installing it on your hard drive.
You won’t be able to save anything to hard drive, but you could save to an external drive or usb drive.
Heh, what a coincidence, I’m planning on double majoring with computer science and composition. 
I hope I will be forgiven if I am reanimating a dead thread! The best option right now (IMO) is ABC notation - text-based, simple, and completely portable as well as human-readable with a little practice.
There are programs available for writing/editing, from which I recommend ABCedit by Joop Cooleghem and ABC navigator 2.0
(hint: to write a chord in one voice - [abc] , to write in different voices v:1 abc )