Corked cylindrical bottles first appeared in the 18th century to hold wines that would be aged. Square bottles would have been more eocnomical, but were popular only in Holland where they held gin. It is said that the shoulders of the Bordeaux bottle are good for catching the sediment at the bottom of an aged bottle but that it is an incidental benefit of the design, not its primary function.
With wines from other nations the bottle may indicate that the wine is similiar in style to French Bordeaux or Burdgundy. Californian, Australian and South American wines usually follow French wine-bottle shapes. Californian cabernets are sold in Bordeaux bottles because Cabernet Sauvignon is the most common Bordeaux grape. But in some countries the shape of the bottle may be simply a whim of the vintner.
Even within Europe, there are other bottling traditions. German wine-makers often use tall, elongated Mosel bottles, while some Spanish and Portuguese wines that are drunk 'young' feature squat 'onion bottles', a throwback to the 18th century, when all wine was drunk young and did not need to be stored. From the onion, bottles developed into a 'mallet' shape with a squarer body.
Champagne was transported around in thick bottles crafted to withstand the pressure of the bubbles within. The deep 'punt' or indendastion in the bottom adds tensile strength, which allows the bottles to be stacked upside down during the fermentation process.