The fine folks at Headliner.fm have written a blog post running down 10 essential programs for musicians. In with a bullet at number 8 is Sibelius 6, about which Nick from Headliner writes:
When it comes to notation software, nobody does it better than Sibelius. This intelligent and highly capable program allows you to score your music either by on-screen, note-by-note writing or by playing it from your MIDI keyboard, and comes with an instrument library so that you can check on how your composition sounds with ease. Sibelius is perfect for arranging anything and everything from horn sections to choirs to full-fledged orchestras, but you might not get too far without a strong understanding of music theory, harmony, and the dynamics of composition. One of its cooler features allows you to sync Sibelius with your DAW software (i.e. ProTools, Logic) for easy over-dubbing and playback using ReWire. At $499.00 Sibelius isn’t exactly cheap, but luckily they offer Crossgrade and Education versions that support the same essential features at a fraction of the cost.
Pro Tools gets a mention too, of course, at number 3, and Nick calls it “the industry standard in the digital recording world.”