Big name brands of cola include:
Coca-Cola - The biggest and oldest of them all, 'Coke' was also the first cola drink to use carbonated water. As well as cola nuts, coca leaves (including the cocaine within them) were used in the syrup, hence the name 'Coca-Cola'. The original recipe was invented in 1886 by a Mr Pemberton at the Pemberton Chemical Company in Atlanta. The cocaine level in Coca-Cola was a worry from quite early on, and it was reduced by the makers until only a trace remained. Apparently the makers couldn't totally separate cocaine from the coca leaves and were worried they'd be sued if they used the name 'Coca-Cola' for a drink which didn't contain any coca leaf. When technology allowed, they removed the last (fairly harmless) vestiges of cocaine in 1929, and the current formula uses coca leaves imported and 'decocainized' under special licence from the US government's DEA. The curvy logo was drawn up by one of Mr Pemberton's employees at the time of its invention in 1886. The famous curvy bottle was introduced in 1916. The high point of the so-called 'Cola Wars' came when Coca-Cola, faced with a sliding share of the market compared to Pepsi and other soft drinks, decided to change the taste of Coke. Introduced in 1985, 'New' Coke was meant to be more like Pepsi but a terrible marketing campaign including the total removal of 'Old' Coke from the shelves lead to an enormous public outcry in the United States. The old formula returned under the banner 'Classic Coke', and 'New Coke' sank quietly into the background.
Pepsi - Second place challenger Pepsi Cola was invented in 1898 by a pharmacist called Caleb Bradham. Pepsi has always tried to be the cooler alternative to establishment-friendly Coke, but has never quite managed to knock it into second place although it came very close during the 'New Coke' marketing disaster in 1985. Pepsi Cola takes its name from an ingredient named 'pepsin', which is a type of protein-degrading enzyme used in food processing and a natural product of your stomach lining.
Virgin Cola - Richard Branson attempts to extend the Virgin franchise into your fridge. So far it has failed to overtake Pepsi in the UK as he claimed it would, and unlike Pepsi or Coke it's relatively hard to find cans of Virgin Cola on sale anywhere. Cross-promotion has been Branson's main weapon, serving Virgin Cola on Virgin Atlantic flights and (until they closed down) at Virgin Cinemas. Many promos tie in with Virgin Megastores as well. For a while the half-litre bottles were called 'The Pammy', an attempt to link their curvy nature to the immense popularity of alleged actress Pamela Anderson at the time of the small bottle's launch. Virgin Cola has put in an occasional appearance on popular US sitcom 'Friends', but then so has Virgin Atlantic and Mr Branson himself.
Jolt Cola - Largely only available in America, you sometimes spot a can or two of this at more open-minded newsagents in the UK (the kind that stock Coconut Toffee Crisp and Fry's Chocolate Cream). Its main selling point is that it has more caffeine than any other brand of soft drink, and has even extended this claim to its non-cola products. Popular with computer programmers, while many might buy it because they need to work late into the night and are sick of coffee, my personal feeling is that this is trying to appeal to the more 'I can take it!' macho-nerd side of the market, in the same way strong beer companies might appeal to those who ask for the hottest curries.
Supermarket Own-Brand - All supermarkets make their own brands of cola, which can vary in quality tremendously. Many taste very soapy, and are only really good as mixers, many are too sweet, but some manage to be passable. Sainsbury's caused a furore when they introduced a slightly bitter own-brand 'Classic Cola' range, which had a very vaguely Coke-like stripe under its rather boring logo. They removed the stripe after complaints from Coca-Cola, but the resulting publicity together with a surprisingly nice flavour made Classic Cola sell relatively well and become a minor brand in its own right. The British Basketball League continues to be sponsored by Classic Cola, for example.
Organic Cola - Only one brand spotted of this, but the sample tested was a tepid vaguely sugary mixture with, get this, sediment. Yes, you drain your glass to find the bottom of it covered in brown gunge. Not for the mainstream, your correspondant suspects it was deliberately made more difficult to drink in an attempt to somehow suggest it's more 'natural'.
Schweppes - A special mention here for an extinct brand. Schweppes Cola had the perfect balance of bitterness and sugar, together with a wonderful lemony zest to top it all off. Shame they stopped making it, but that might have had something to do with Schweppes becoming (for a while) the official licenced manufacturer of Coca-Cola in the UK.
As a final note, it should be put on record that cola mixes extremely well with dark rum.