The upcoming WH Series aka 3-in-1 Walkman are headphones with a built-in digital music player. Available in 4GB and 16GB capacity with 20h battery life. They can also be used as normal headphones or as personal speakers.
Sony mashes up two of their popular franchises with the camouflage Metal Gear Solid: Peace Walker W-Series Walkman. Pre-loaded with the MGS soundtrack and out this June for about $60.