The entire final scene, or more specifically everything that happens afterwards.
Lestat: I assume I need no introduction?
Santiago's upside-down dance and the cheeky humiliation of Louis that followed.
Claudia slitting Lestat's throat. Also special because of the utterly malevolent grin Claudia wears.
Lestat: Put me...in my coffin. Claudia: I'll put you in your coffin! (slits his throat) There!
Lestat crashing through the window of Louis' flaming mansion to pull him out. Followed up by his spectacular Shut Up, Kirk!... or better say, "Shut up, Louis!"
Lestat: Perfect! Perfect! Just burn the place, burn everything we own! Have us living in a field like cattle! Louis: You thought you could have it all. Lestat:Shut up, Louis!
Brad Pitt didn't enjoy working on the film, but his sorrow and fury is truly palpable in this scene; especially the Death Glare he gives the troop before, when Armand has to pull him away.