Serenity:

Hoban ‘Wash’ Washburn: This landing is gonna get pretty interesting.
Capt. Malcolm Reynolds: Define “interesting”.
Hoban ‘Wash’ Washburn: [deadpan] Oh God, oh God, we’re all going to die?

Ghostbusters:

Dr Ray Stantz: Hey… Where these stairs go?
Dr. Peter Venkman: They go up!

On the subject of great film quotes (Films)