The four factors in deciding fair use include: the amount of information you are using, where you should concentrate on using only what is needed and not taking advantage of your position; the nature of the original work, meaning why was the original work created; the commercial value of your intent, so that you do not remove economic gain from the creator or copyright owner; and the purpose for which you are using the information. Acceptable reasons include educational purposes, newscasts, scholarship or research, and critical comment.
Whenever you are in doubt, it is better to err on the side of caution. If you really have to pull justifications out of left field, then you're probably lining yourself up for a lawsuit.
Oh, great movie today, too!