Apu Nahasapeemapetilon is the best too:
Apu (when Homer is opening the chocolates, trying to find the winner): "Please sir. I've asked you nicely many time. You leave me no recourse but to... ask you nicely again."
Apu: "Shut up."
Homer: "And then you could..."
Apu: "Please shut up."
Homer: "Or you could..."
Apu: "I can't believe you don't shut up."
Apu (to Skinner, who was going to write a book based on a stroy VERY similar to Jurassic Park): "Oh no, no no no. You cannot do that. It is one of the greatest films and books of all time. It won 19 OScars. The book sold 190 million copies... (Ten minutes later) That is a stupid idea. WHAT WERE YOU THINKING?"
Apu (to Elton John): "Yes, because "Someon saved your Life Tonight". "
John: "Stop it. Just stop it."
Apu: "Ooh, "The Bitch is BAck!" "