Here's a description of the Maine Coon breed taken from a Maine Coon breeder website:
The Maine Coon is one of the largest domestic breeds. They are tall, muscular, and big-boned; males commonly reach 13 to 18 pounds, and females normally weigh about 9 to 12 pounds. Add to that two or three inches of winter coat, and people will swear that they're looking at one big cat.
Maine Coons develop slowly, and don't achieve their full size until they are three or four years old. Their dispositions remain kittenish throughout their lives; they are big, gentle, good-natured goofs – the gentle giants of the cat world. Even their voices set them apart from other cats; they have a distinctive, chirping trill, which they use for everything from courting to cajoling their people into playing with them. Maine Coons love to play, and many will joyfully retrieve small items. They rarely meow, and when they do, that soft, high-pitched voice doesn't fit their size!
The important features of the Maine Coon are the head and body shape, and the texture and "shag" of the coat. The head is slightly longer than it is wide, presenting a gently concave profile with high cheekbones and ears that are large, wide at the base, moderately pointed, and well tufted inside. They are set well up on the head, approximately an ear's width apart. Lynx-like tufting on the top of the ears is desirable. The neck should be medium-long, the torso long, and the chest broad. The tail should be at least as long as the torso. One of their most distinctive features is their eyes, which are large, round, expressive, and set at a slightly oblique angle. Overall, the Maine Coon should present the appearance of a well balanced, strongly built, rectangular cat.
Throughout their history there has been no restriction on the patterns and colors acceptable, with the exception of the pointed Siamese pattern. As a result, a wide range of colors and patterns are bred. Eye colors for all coat colors range through green, gold, and hazel (green-gold). Blue eyes and odd eyes (one blue eye and one gold, green, or hazel eye) are also permissible in white cats
Many people consider Maine Coons the perfect domestic pets, with their clown-like personalities.