This thread click here what is your favourite scene in a movie. I have several The sanity clause scene in the Marx Brothers "A Night at the Opera" Too many to mention from Laural & Hardy and the Landing of the spaceship in Close Encounters of the Third Kind to name but a few.
I'm not sure about favourite scenes, but this is one of my favourite lines is this from Ferris Bueller's Day Off...
"Um, he's sick. My best friend's sister's boyfriend's brother's girlfriend heard from this guy who knows this kid who's going with the girl who saw Ferris pass out at 31 Flavors last night. I guess it's pretty serious."
or this from the same film
"Life moves by pretty fast. If you don't stop and look around once in a while, you could miss it."