First things first, using the PS2 for playing DVD movies can throw your lens out of alignment, causing it to not play games or if it still plays them it will not work very well after repeated use. The reason that the PS2 actually plays DVD's is that the newer PS2 games are made in DVD format. The system was not designed as a DVD player, it was designed as a game console. So in that respect it is my advice that you get yourself a DVD player (doesn't have to be the best) for movies, and leave your PS2 to what it does best, play games.
Enjoy,
Greg