Planetary [bloom.io] is the latest "pop-cultural instrument for data expression and exploration" by Bloom.io. It allows for a completely different look at your music repository, going well beyond the traditional approach of browsing through long track lists or album covers.
In the app, artists are represented as stars, albums are planets, and tracks are moons. Artists can be filtered by choosing the first character of their names, which then creates an alternative space constellation that can be further explored.
Available for the iPad, and completely free, here.