If you want to avoid a cat fight, don't get into a discussion with Siamese breeders over the different types of Siamese cats. The Cat Fanciers Association modern Siamese breed standard specifies a wedge head, while classicists have formed their own organizations promoting the apple head and traditional Siamese.
Siamese Color Points
Siamese cats are easily recognizable by their distinctive blue eyes and color points. The "points" are the darker shades on the head, ears, legs and tail. The seal point Siamese has dark brown points on a lighter body, ranging from fawn to nearly white. The nose and paw pads are black. The chocolate point Siamese appears in various brown shades with a lighter body, and pink nose and paw pads. The blue point Siamese sports gray points and and lighter fur with a bluish cast, along with a gray nose and paw pads. The lilac point Siamese boasts gray points with pink highlights on a white body, and gray/pink nose and paw pads.
Cat Fanciers Association Breed Standard
The Cat Fanciers Association, the country's largest purebred cat registry, states in its breed standard that the Siamese head is a "long tapering wedge." The wedge begins at the nose, flaring straight out to the ear tips and creating a triangle. The skull is flat, and there's no dip in the nose or bulge over the eyes. The Siamese cat profile should have a straight line from head top to nose tip. The body standard calls for a long, tubular cat with a "distinctive combination of fine bones and firm muscles."
The Apple Head Siamese
The apple head Siamese, also known as the traditional Siamese, resembles the original cats imported to Europe during the Victorian era from modern Thailand. No wedge head here -- the apple head Siamese's noggin is quite round; his body is much heavier than the modern Siamese. His tail is not as long as that of the wedge head. If the wedge head resembles modern art, the apple head Siamese is an Old Master.
The Classic Siamese
The classic Siamese is a mix between the apple head and wedge head types, and dates back to some of the earliest importations from his native Thailand. He's larger than the traditional or wedge head, with a bigger bone structure. While his head has some wedge to it, the shape is not nearly as extreme as the modern Siamese. The classic and traditional Siamese have thicker coats than the modern version.