Name one highly underrated movie

[Q?]

Preferably an old or a obscure movie please

I'll start with this.
Close Encounters Of The Third Kind.
I'm continually amazed that this was released in 1977, first of all the performances were great and believable, especially Cary Guffey who "played" Barry (the kid) was a near miracle, thanks to Spielberg ingenious way of directing.
What I'm more amazed about are the special effects, the scene

[Show spoiler]were Roy is in his car and a UFO is hovering above him was a simple effect, the car was just on a "gimble" (not sure what it's called) and the camera was just locked in place,

however simple that was made, it was just incredibly brilliant! It gets me everytime, my jaw just drops.
Also the five note melody which John Williams made (out of thousands) is also something that has stayed with me since childhood, I just love it.

The reason why I think that this movie is very underrated is because I feel that not that many appreciate it, the special effects alone rival that of many of the movies today, it just so damn believable to me, which is more important to me however simple they are made. The BD is very grainy, very very grainy but I prefer that over digital manipulation any day.

Discuss this movie if you please or name one movie you feel is highly underrated.