My favourite would always be Back to the Future trilogy.
These are some other movies I like in no particular order for the moment. Sorry if I repeat titles mentioned before by you guys.
Ghostbusters The Goonies The Breakfast Club Superman movies with Christopher Reeve Gremlins Gremlins 2 Ghostbusters 2 Chitty Chitty Bang Bang The Sound of Music Dumbo Escapade in Japan Weekend at Bernies The Sword in the Stone Groundhog Day The Wizard of Oz Supergirl Teenwolf Return to Oz Care Bears - The Movie My Little Pony- The Movie Big Who Framed Roger Rabbit? Indiana Jones and the Temple of Doom Indiana Jones and the Last Crusade Karate Kid Mary Poppins Thoroughly Modern Millie Spaceballs Grease Grease 2 Bedknobs and Broomsticks Robin Hood (Disney) Police Story Edward Scissorhands Armour of God Mr Vampire It is Mad Mad Mad World 2 The Banquet Merry Christmas Some Stephen Chow movies Happy Ghost 3 Eight Happiness Flash Gordon Dot and the Kangaroo Teenage Mutant Ninja Turtles 1 and 2 The Terminator Big trouble in little China Isle of Fantasy Zu Warriors Tremors Tom Thumb Muppets take Manhattan Robocop Bill and Ted's Excellent Adventure Clash of the Titans Drunken Master Honey I shrunk the kids
I have to stop here, it's getting too long. There are still too many to list.