Music (in history called Walkman) is luxury music application preinstalled in Sony XPERIA smartphones. Every new version brings many improvements like support Music widget in non-XPERIA launchers, possibility to browse music via folders or improved design with multiple views that gives instant access to your favourite music. I thing that latest Music application (9.0.0.A.2.0beta) is best music player in stock Android ROMs.

Latest Music 9.0.1.A.4.0 beta (download apk)
Latest Music 9.0.0.A.0.1 final (download apk)

•Application renamed to Music
•Settings moved to drawer
•Mediaserver moved to Settings
•Faster startup
•Reduced app size
•New Full player
•Playqueue in drawer
•New context menu icon
•Widget stays in notification after pause. Swipe to dismiss in Android 5.0 (Lollipop) or use "X" button (older platforms)
•Bugfix: Title issue in homescreen widget
•Bugfix: Player color picker
•Recent apps color (Lollipop only)
•Previous button on lockscreen (Lollipop only)
•Made tabs use more space in "My library"
•Sleep timer (beta only)
•Quick play button (beta only)
•Sleep timer show time to end (beta only)