I use Google play music and Spotify for streaming. Also use Apollo (CyanogenMod music player) when I want something different.
Smart audio book player is a pretty good app. There are many others in the play store.
Launchers differ on how they change the look and UI of the device. Some such as Nova allow you to hide bloatware and manually change app icons. Themer and Buzz launcher differ in that they let you apply themes that others have created.
I personally think SwiftKey is the best keyboard due to its predictive text and flow typing. There are some emoticon centric keyboards and plug ins for various keyboards.
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