can an expert please help me think this thru. which amkes the most sense--portable dvd, personal video player or lightweight laptop?

i am flying early next week and wanted a portable dvd to take with me. figured it would be good for the kids on long trips in the car or when flying, too. thought the best one for me was a toshiba at 180$ because it boasts a 3.5 hour battery.

but then i heard about smaller portable personal video players (i think that is what they are called) like ipod video, toshiba, etc for about 300$. i don't think this would be so useful for kids to share on long car or plane trips, but maybe it is the way to go for other reasons? does it have more advantages than a portable dvd?

and of course there is the idea to get a lightweight laptop, which would be great for movies and office work on the plane, even in the car, but is heavier, and more expensive--and many have a short battery life. what would be the least i could spend on a ;aptop that would be lightweight enuf to take on a plane, and have a long enuf battery life to make it worthwhile? what other features should a laptop have if i need it mostly for office documents and movies?

thanks!