If you're looking to do basic home recording, or need to edit sound files, then this is probably the tool for you. It's a free, open source application which can be a powerful tool, great for getting simple tasks done with the minimum of fuss while also offering more powerful options for those who need them.
Particularly useful features include:
"LilyPond came about when two musicians wanted to go beyond the soulless look of computer-printed sheet music. Musicians prefer reading beautiful music, so why couldn’t programmers write software to produce elegant printed parts? The result is a system which frees musicians from the details of layout, allowing them to focus on making music. LilyPond works with them to create publication-quality parts, crafted in the best traditions of classical music engraving."