Reasons why "Forbidden Planet" is truly worth a good watch.

1. I'll go ahead and lead with the best - a monkey gets shot at with lasers by a robot.
Seriously. Monkey. Laser. Robot.

2. Great titles.
Just the lettering sense, not much in the animation department there, but great look.

3. Animation Styles
There's an excellent scene where the steel shutters close and it is clearly some stop motion action. It is jarring but chanrming.
The monster is drawn in by Joshua Meador, who was an animator from Disney.
Great scene where the invisible monster is coming and you just see it's tracks in the dirt, then it walks up the stairs and bends the steel stairs.

4. Excellent set designs
Created by Cedric Gibbons who won and was nominated for a ton of Academy Awards for Art Direction. The shot below is of the three characters on a walkway.

5. Music
The soundtrack is all "electronic tonalities". It's credited with being the first completely electronic film score. Very strange, but very cool.

6. Finally, Robbie the Robot generates 480 pints of whiskey overnight.
I need this Robot.