Southern Comfort

Southern Comfort is an American, fruit flavoured whiskey liqueur. Originally created by bartender Martin Wilkes Heron in New Orleans in 1874, the brand has gone through closure during the Prohibitions and transitions and transfer of ownership.

Spirit Historian Chris Morris describes the original recipe of Southern Comfort in an episode of The Thirsty Traveler titled "A River of Whiskey"

Heron began with good-quality bourbon and would add: An inch [2.5 cm] of vanilla bean, about a quarter of a lemon, half of a cinnamon stick, four cloves, a few cherries, and an orange bit or two. He would let this soak for days. And right when he was ready to finish, he would add his sweetener: he liked to use honey. - Wikipedia

In the United States, Southern Comfort is available as 42 US proof (21% ABV), 70 US proof (35% ABV), 100 US proof (50% ABV), and 60 US proof (30% ABV) in Australia. Varieties including additional flavorings, such as lime and caramel, were introduced by Brown–Forman in the latter years of their ownership. These were discontinued by Sazerac - Wikipedia

Baileys Irish Cream

Bailey's Irish Cream is an Irish cream liqueur, a liqueur is an alcoholic drink made of distilled spirits and flavorings such as sugar, fruits, herbs, and spices. They can be rightfully christened as the descendants of herbal medicine. The Bailey's Irish Cream is a sweet, cream and cocoa flavoured thick liqueur with Irish Whiskey being the base alcohol and is one of the most popular liqueurs used in cocktail creation.

Bourbon

American's don't need to be lectured on Bourbon, but still, let's put it in record like all other spirits. A Bourbon in American spirit is a barrel-aged distilled liquor made primarily from corn. The name might have been derived from the French Bourbon dynasty, or from Bourbon County in Kentucky, or Bourbon Street in New Orleans, both named after the French Dynasty.

Technically, most whiskey made in America are legally classified as Bourbon, although Bourbon is in spirit a Southern Whiskey with special connection to Kentucky. Note than although Tennessee Whiskey is classified as Bourbon, Tennessee distilleries do not prefer their whiskey to be unique and referred to as Tennessee Whiskey only.

Distilling came to Kentucky in the late 18rth Century with the Scots, Scot-Irish and other settlers including English, Welsh, German and French, and they brought with them their distilling techniques and ageing processes in charred oak barrels. The charring is what gives the Bourbon the brownish colour and distinctive taste.

To be a legal Bourbon, a whiskey has to meet the following criteria

Produced in the United States and Territories (Puerto Rico) and the District of Columbia
Made from a grain mixture that is at least 51% corn
Aged in new, charred oak containers
Distilled to no more than 160 (U.S.) proof (80% alcohol by volume)
Entered into the container for aging at no more than 125 proof (62.5% alcohol by volume)
Bottled (like other whiskeys) at 80 proof or more (40% alcohol by volume)

Vodka

Vodka is an European clear distilled alcoholic drink that has been one of the most popular drinks across the world .

You'll find it to be the most popular spirit in drink making because of it's neutral taste and absence of flavour and colour.

Vodka often replaces Gin in many traditional cocktails

Vodka is known to be good for the heart, and if consumed in moderation, can prove to be good for cardiovascular health

Note that these days there are flavoured Vodka available in the market too, and some cocktails do make use of them.