Which movie should I watch? - Top 100 English Project?

Top 100 according to who? If it's imdb then try American Beauty. It should be easy to use for this topic and it's number 37 on the list http://www.imdb.com/chart/top

Citizen Kane is hands down the best film out of all of those for a paper on the American dream. But the next I would choose is Some Like it Hot. I don't care much for American Graffiti, but that speaks on the American dream better than One Flew Over the Cuckoo's Nest. However, OFOtCN could have a really interesting angle to it, which could give you an automatic A if you do it right.

American Graffiti

i am not sure if its on the top 100 yet but the film is called "Racing Dreams"

www.racingdreamsfilm.com

basically its a documentary-story about 3 young children ages 11,12 & 13 who want to be nascar race car drivers and currently kart racing is their passion....

and i think its a wonderful american dream theme because "nascar" is American and very popular and it shows how young kids can be so motivated and work so hard at succeeding in a career from a young age.

Its coming out in theatres tomorrow-its a limited release though so if your in the South you may be able to catch it in theatres..but they will expand to more theatres as time goes by...

Anyways do check it out -it has won many awards so maybe your teacher may apporve of it!!