re: Recomend classic movies to watch

So im updating my netflix que:
Previous top six:
1. The Bridge on the River Kwai. No explanation needed.
2. A History of violence. Wanted to see it since the previews first came out. Plus i hear there is some hot maria bello bush action.
3. True Romance. Dont know how i havnt seen this one
4. The A-team. Loved the series. Heard the movie was at least worth the watch.
5. The Sting.
6. Lawrence of Arabia. As much of a classic as this is I have no knowledge of any spoilers.

Added.
1. Arsenic and Old Lace. Had heard of it, was the most recommended movie.
2. Witness for the prosecution. Thanks for the suggestion Freauxzen
3. Guess who's coming to dinner. Sidney P. is awesome.
4. Captain Blood. My surprise pick. No knowledge of the movie, only seen one Errol Flynn flick prior.
5. Mr. Smith goes to Washington. One of my top favorites. Havnt seen it in a few years.

Once again, thanks for the suggestions. Ill try to get to all of them and keep everybody posted.