I like this Belkin 15.4 inch messenger bag. It is a lightweight bag which is mostly suitable for dynamic young people. The compartment for laptop is made from scratch-free plush material. As you can review from the image, it is a very comfortable messenger bag with adjustable strap and enough extra pockets for mp3 players, external hard disks, credit cards, pens etc.
You can use the special pouch for power cable and other laptop accessories. This cool messenger bag has many color variations, Jet/Cabernet being the most popular. With limited lifetime warranty.

