The technologies to convert a dvd to play on the N800/810 are exactly as easy as the tecnologies to save and play a dvd on your laptop.

But if your primary interest is in watching movies, I would think you'd be better off buying a subscription to Netflix and maybe a bigger tv.

One difference between a tablet and other medias that the screen is smaller. No tablet can fix that.

As far as disk space usage goes, you should have room for a few movies with a 2-gig sd card.