Right now all sorts of programs, applications and data are stored to the cloud, hosted on multiple, Internet-connected servers. To access your goodies, you simply have to remember your login name and password. Oh, and of course, you need Internet access. And for streaming music, video and other staples of a multimedia dinner, you need a fast, dependable connection.
A lickety-split connection is even more indispensable when it comes to streaming audio from services such as Pandora, Spotify, Amazon Cloud Drive, iCloud and Google Music. All of these companies let you stream thousands of songs from their servers to your mobile device, no matter where you might be.
That flexibility of availability is a wonderful thing -- how cool would it be to blast music from the soundtrack of "Raiders of the Lost Ark" while you're spelunking in Carlsbad Caverns? The awesomeness would be unmatched, but that dream is unlikely to happen without a great 4G connection.
After you find a 4G signal, streaming should be a snap. The only real challenge might be your data transfer limits. As more and more users jump to 4G, expect providers to cap (or charge exorbitantly for) very high data usage.