Excellent suggestions so far. Most of the ones that initially popped to mind have been mentioned, so I'll throw a feew more out....
John Coffey rides the lightning - The Green Mile
Goose gets killed ejecting from the plane - Top Gun
"Run, Forrest! RUN!" - Forrest Gump
Vader tells Luke he's his father - Empire Strikes Back
Phoebe Cates showing her boobs coming out of the pool - Fast Times at Ridgemont High