Seeing others use linux for music production is inspiring. I'm currently in the stages of building a home music studio and I'm strongly considering giving linux a go instead of going with a mac mini. However it's really hard giving up Pro Tools...
I switched to Musecore. Although I generally eschew GUI apps I much prefer it to LP: I can see my editing changes directly without the "compile, run" steps. My efforts are less DRY, to continue the programming metaphor (eg copy/paste the chorus) but that's acceptable. I don't plan on writing any massive symphonies. As @rekado elsewhere on this page, I don't have to act-as-programmer when I'm making music.
Musecore has had lots of criticism of its design but that area has apparently improved a lot recently. It might be "Word for music" but it's a mostly-complete-but-simple version (so... Word 6? AbiWord?). Works for me.
I found Frescobaldi to be a decent compromise in that regard as it serves as a decent Lilypond editor while keeping the rendering of the score up to date at the same time.
Personally, I'm going to experiment a little more with tighter Emacs and perhaps Org mode integration. I don't care for the full score at all times, so using Lilypond as a server and sending it only short snippets to be displayed in an Org mode babel buffer might be a viable option.
(I know that you can tell Lilypond to skip time and only start rendering after some offset, but I'd rather not have to keep adjusting that offset number all the time; it also doesn't work so well for pieces with different odd meters.)