Since we'll be living aboard and likely sitting at a marina next winter, my wife wants to be able to watch movies. Preferably on a screen bigger than her 13" MacBook Air, and with external speakers. One option is to get a 17" laptop but it's overkill since we already have the Macbook. Sanyo makes a portable DVD player but the screen is only 14" so no gain.

Are there any simple options that don't kill the budget, take tons of space or electricity, but give a good movie experience ?