A smart-looking device from Sony, the NWZ-E473BLK can play music or video or display photos in addition to providing FM radio. It is quite small and will easily fit in your pocket.
Retaining the time-honored 'Walkman' designation, this fairly advanced piece of kit is compatible with both iTunes and Windows Media Player and is claimed to be capable of up to 36 hours of playback on its rechargeable lithium-ion battery. However, that figure is only valid for audio; video playing time will be much shorter, as indicated by the manufacturer's average figure of 6 hours.
Sporting a smallish 2-inch high-brightness color LCD display with a resolution of 320 x 240 pixels, this player has 4GB of storage - a capacity best described as adequate nowadays, especially when it comes to video. However, if thinness is important to you, you will be unlikely to do better than this attractive little device.