Except purchasing movies from iTunes Store, you can also rent movies from iTunes Store, this is called iTunes M4V rentals. After you start watching the rent movies, you can stop it or continue it again next time. But you can only 30 days from the time of rental to watch your movie, and 24 hours (in the US) or 48 hours (elsewhere) after you've started viewing to finish it. Once the rental period expires, the movie will disappear from your iTunes library.
If you want to keep some classic films, what will you do? Purchased ones? If you have M4V Converter, but you wouldn't have to pay for movies, when you watch movies, you can convert it at the same time. It is really a win-win solution.
M4V Converter Plus for Win is a powerful iTunes Video Converter, which can convert any iTunes videos even DRM protected ones, the only condition is that you can play these files on iTunes normally.