This is just some relevant titles from the Halloween must watch list I have, and that's not even considering more mature movies, because all of those here were meant to be shown to my 5 year old sister.
Practical Magic
The Addams Family
Casper
The Haunted Mansion
Coraline
Matilda
Ghostbusters (1 and 2)
Frankenweenie
The Legend of Sleepy Hollow (Disney animated)
Poltergeist
ParaNorman,
Hotel Transylvania,
Gremlins (1 and 2)
Pan's Labyrinth
The Black Cauldron
The Great Pumpkin
The Boxtrolls
Mom's got a Date with a Vampire
The Little Vampire
Harry Potter (mainly 1 and 2)
Buffy the Vampire Slayer
Goosebumps (the series, NOT the movie)