Needless to say that there is a wide range of prototyping tools out there and I won't say which one are the best ones because there isn't one. I liked to say it all depends on your workflow and what's your purpose of this tool.
'Discover the world of Pharrell Williams' is a great example of beautiful branding and UI/UX work. The project shared by Ronald Gijezen and Robbert Schefman exemplifies a powerful combination of print style applied gracefully to the web and mobile devices. I love that some screens could actually be amazing posters hanging on my wall, that's a clear statement of the level of craftsmanship behind this project.
Follow, join and be inspired by Pharrell Williams. Get your daily dose of inspiration and creativity on www.pharrellwilliams.com. Pharrell Williams, also known by his mononym Pharrell, is an American singer-songwriter, rapper, record producer, and fashion designer. Williams and Chad Hugo make up the record production duo the Neptunes, producing soul, hip hop and R&B music
For more information check out http://www.exoape.com/pages/projecten/pharrellwilliams.html