Another service you might want to try out is Pandora. I'm not sure how Jango operates, but as far as I know, Pandora is the only online streaming site to use something like the Music Genome Project.
In a nutshell, most streaming sites will look at the artist you've chosen, determine their genre, and then give you more artists it considers to fit that genre. Pandora goes much deeper. The Music Genome Project looks at nearly 400 different attributes for any given song, such as beat, tempo, chord progression, instruments, bass lines, everything. That allows Pandora to offer a more diverse selection of songs in response to a given song or artist, things that you would have never thought to associate yourself, or have never heard of, yet fit in nicely with the station you've created.
That depth, combined with the ability to give thumbs up or down to any song (which influences what style of songs the station will then give you), or to combine stations if you want a mix of styles (some Daft Punk mixed in with some Decemberists mixed with some songs similar to "Don't Stop Believin'" by Journey), in my experience leads to more interesting and diverse results.
I'll be giving Jango a look though, I can always use more music!