There is a lot of choice when it comes down to portable devices for on the go entertainment, from basic storage / playback "boxes", through gadget rich touchscreens, to audiophile quality FIIO type mp3 players.
I wanted a solid multimedia capable device with proven reliability and quality, which has a track record of surviving the rigorous commuter trip or longhaul flight, and with a battery which lasts the journey. In addition I needed a capacity which did not require a high level of selectivity when deciding which of my extensive music and video libraries to transfer to the device - an issue that I found increasingly frustrating with my previous 16GB Nano.
This led to just one option - the 160GB IPOD Classic. Massive capacity (I just sync my entire library), long battery life, iconic design which I actually prefer to touch screen, colour screen, and still small enough to be incredibly portable with shirt pocket sizing.
Provided you can live with apple software limitations I would have no hesitation in recommending the Classic as a must have accessory for reliable on the go multi-media.