1) good entertainment value (I should not feel like walking away from it) 2) good acting ( this can be a definite deciding factor on how good a movie is) 3) believablity ( I do not like movies that do not have a path of logic to them)
#1 - Character Development - if you don't feel for the characters you're not going to care what happens to them.
#2 - A solid plot - no cheats - too many movies I've seen will make up their own rules as they go along. If something wasn't true in one scene, it can't be true three scenes later. (Especially referring to horror movies)
#2 - A good ending - So many movies anger me when the main character wakes up and it was all a dream, or that everything just falls together at the last moment and everyone lives happily ever after.