¿which is your favorite movie vs what is your favorite movie?
which one is your favorite movie can also be an option? :S

Question

Answer

"which one" is: out of A, B, C,... which one of these is your favorite?
"what is" is: out of every movie ever, what is your favorite?

Answer

Thank you Dana :D

Answer

In general "What is your favorite movie?" is correct.
"Which (one) is your favorite movie?" is correct if you give the person a list of movies to choose from.

For example:  "I have the movies Shrek, Home Alone, and iRobot. Which one is your favorite?"

Evden çıkmadan dil öğrenme fırsatını kaçırmayın. Deneyimli dil eğitmenlerimizden oluşan seçkimize göz atın ve ilk dersinize şimdi kaydolun!