One of the world’s most respected music publishers is G. Henle Verlag. I have several Henle scores — including some that have been engraved in Sibelius — and their commitment to beauty and clarity in the scores that they publish is practically unrivalled.
Henle still employ a variety of techniques in producing their beautiful scores, including software programs like Sibelius. But few people know just how involved the art of music engraving was in the days before computers. Henle’s web site includes some fascinating videos (in Windows Media format) that will give you a tremendous insight into the process.