The best dog scene? Dirty Harry, firing "the world’s most powerful handgun", while chowing down on a dog served up by Woody Parfrey.
Also good is when Eastwood tells the fat detective who is eating a dog, "NOBODY puts ketchup on a hot dog."
Then, in "Hickey & Boggs", Robert Culp and Bill Cosby (down on their luck LA PIs) are seen ordering chili dogs at Pink’s, on La Brea. I think they each order two, then Cosby says, "No, THREE". Ha.