So do you have a favorite actor or actress? Maybe Tom Cruise since he's a hottie, well you are most likely to get some extra readers by adding some cool actors that readers love. I know if I saw some Tom Cruise I'll be checking out the book, but this is not a must have. 
In most cases you don't even have to use a famous person to make a cast list. You don't even need a picture to put in the cast list, you can just put down the name and maybe a little about themselves just to give the audience a general idea of who they are.

Now all together you don't need a cast list, if you don't want to surprise the crowed or take the extra time to put details of that character in your story you don't have to. Also take note that your characters should be able to stand on their own two feet without crutches (A.K.A a famous actor) it's alright to picture someone famous, but when making the character and describing them don't sit there and be like this character looks exactly like Snoop Dog.