[LAU] notation software?

[Kim Cascone]

I've tried most of the low hanging fruit for notation apps on Linux
and the best one I've used so far is:
http://www.musescore.org/

Lilypond is good for doing touch-up work or adding symbols Musescore 
can't handle

caveat: the front ends available for LP leave a lot to be desired
and unless you like writing scores in a markup language (see below) then 
I suggest something like Musescore

Lilypond example:

\relative c'' {
  \key g \major
  \time 6/8
  d4 b8 c4 a8 d4 b8 g4
}