hmmm so many great scenes:
When Ilsa Lund walks into Ricks for the first time, Sam sees her and looks like he'd seen a ghost. She asks to play "As Days Go By" when he finally does after come coaxing, Rick comes over p*ssED, sees her, and then there's the whole breakdown, followed by the infamous "out of all the gin joint in all the world she has to walk into mine"
Batman, one of the opening scenes when he first appears on the roof, gets shot by two theives, the robbers laugh thinking that was easy, then Batman rises, kicks one guy through a door then holds the other over the edge of a roof. "whaa.whaat are you?" "I'm Batman" then throws the guy back onto the roof and walks over the edge to dissapear. Classic
Maximum Overdrive had so many, the first scene in the city by the bank where machines start to take control of themselves and start telling people off. Or when the Coke machine kills the entire little league baseball team except the catcher because he's holding his mask over his face (and his hand is covering the mask) or the ending, the ending was classic!
The Scene in Signs when Mel Gibson realizes all the bad things in life are there to protect him from the biggest tradegy of all (the death of him and his family)
The scene in Swordfish with Halle Barrie and the book
Yoda lightsaber fight is a given
The first scene where we see Darth Vader, when the storm troopers come out, shoot up the place, the smoke clears and there's Vader. First time I watched it after getting out dog, Turk (the dog) when NUTS, barking and growling at the TV as if Vader was there for us.
Staying on the Star Wars topic, in Episode I, when Qui Gone Gin (I know that's spelled wrong, sorry Star Wars gurus) uses the Jedi mind trick on the Gungan leader but they never actually draw attention to it, nor do they ever reference it was done, just the hand movments, and him being agreeable all of a sudden.
I'm sure there's one's I'm missing, but all in all, there's some of my favs. All time favourite? I dunno, tough to decide.