In addition to Sibelius, another well-known piece of sheet music software works with it, is Fretboard by Tom van der Goes. Both of these programs are similar in many ways, though there are differences between them that may be of interest to you. Sibelius and Fretboard both can produce sheet music in standard fingering and key signatures, with additional features such as chords and mode searching. They both also have digital recording capabilities that allow you to print out your finished pieces for other people to play, if you would like.
My personal preference for the best music instruction/speed reading software, hands down, isworks with Sibelius. I have been using it almost since the original version came out, and it has exceeded my expectations time again. It is extremely intuitive to use, and the customer service has always been great. I just wish there were an application that worked as well with Linux as it does with Windows. But, as long as that is not a concern for you, Sibelius will work beautifully in all versions of Linux.