Cell phone is an evolutionary gadget that can integrate a bunch of your other digital needs. The concept of cell phone with mp3 player evolved a bit late as compared to the concept of cell phone with camera. The reason would be less developments in storage and battery issues of the cellphone.
A big percentage of people are just looking for a phone that could also satisfy their music requirements. The basic requirements from a music phone are increased and extendible memory, battery saving issues to have much playing time, dedicated music buttons for interfacing, standardized output slots to export music to standard headphone and hifi systems, a music mode of the phone in which the gadget is nothing but a music player.
Sony ericsson has worked specifically on the music area and created a series of music phones which is also called "Walkman Series". Moreover, sony ericsson has also included a fashion look to its music phones. The most reknown walkman phones from sonyericsson are
w810,
w550 and
w900.