Some good examples here. I’d just mention a few other memorable dialogue scenes:

• all the scenes of McCoy with Spock’s Katra in ST:III, including lines like “Yes, Genesis! How can you be deaf with ears like that?” and "Where’s the logic in offering me a ride home, you idiot? If I wanted a ride home, would I be trying to charter a space flight?"
• in Star Trek IV, the scene with Kirk and Spock in Gillian’s pickup, with Nimoy doing his best Gracie Allen impression. Also, the “No dipshit” bit in the restaurant.