Unbloating the List

After compiling a Top 50 list for all the movies I've seen...I realized that I don't know film as well as I thought I did. My list was full of movies from the last ten years. There were only 3 or 4 films that I would deem as "classic" or older movies. This isn't because I don't like classics, it is because I haven't seen them. So, the only movies I will buy on DVD now are classics and older films. So far I have bought Dr. Strangelove, The Graduate, and Rear Window. I've been desperately trying to find Network and North by Northwest. But anyway, I was hoping some of you could give me some suggestions for older or classic films. That would be greatly appreciated. This new system of buying DVDs has worked, Rear Window has become my 7th favorite movie of all time. Anything with Jimmy Stewart is great. His "aww shucks" voice is always fun to listen to. This reminds me, I was also going to get Vertigo. I'm trying to get into more Alfred Hitchcock. I'm thinking about watching Dr. Strangelove tonight. I haven't decided yet. I was going to watch A Clockwork Orange last weekend but the guy I was going to watch it with watched it before I went over to his house. Oh well. Lastly, is The Shining worth seeing? Some people say its a classic horror and some others say it is just stupid. I'm curious on that. I'll go ahead and stop writing now. I'd love some suggestions for films to watch.