Panasonic DVD-LS50 7-Inch Portable DVD Player
Great quality and worth it
This Panasonic 7\\" portable DVD player is more expensive than no-name brands like Mintek or Initial, but it's also much better quality.  The LCD screen is brighter and clearer (although you might want to turn down the brightness to conserve battery), the build quality is excellent (Mintek and Initial players often feel very cheap and flimsy), and the battery is smaller and lasts longer.  The Panasonic also plays a lot of different formats, and the small speakers give pretty good sound for their size.  Seriously, if you are gonna use a portable DVD player a lot, get this high-quality model instead of trying to save a few bucks on a low-quality brand.