Yes! When it comes to scotch, you should have one good blend (I recommend Famous Grouse) for mixing and one single-malt (I recommend Glenfiddich) for sipping neat.
Of all the scotch cocktails, my favorite is a Rusty Nail: blended scotch and Drambuie. (The latter can also be sipped, either neat or on ice. If you use ice, make it with spring water.)
White rum is best used for mixing, e.g., Cuba Libres and Mojitos. Gold and dark rum can be sipped neat or on the rocks. (Dark rum can also be mixed with black currant syrup or liqueur. Yum-O! :o )
You should have mint leaves and sugar cubes available for mixing Mint Juleps and Mojitos. And quartered limes and lemons.
Rye whiskey, orange slices, sugar cubes, and maraschino cherries should be available for making Old Fashioneds.
Tennessee sour mash whiskey (e.g., Jack Daniels) I find better than bourbon for sipping neat. Try mixing either with Southern Comfort for a Southern version of the Rusty Nail.
Small bottles of chilled spring water are also essential for mixing. So are soda and tonic water. These are best offered in single-serving cans, which chill better and don’t lose their carbonation like big bottles do once they’re opened.
You might want to offer hot cocktails in winter. All you need is hot spring water, gold or dark rum, sweet butter, and dark Muscovado sugar to make Hot Buttered Rum. Keep a small pot of this warm on the stove, adding the rum at the last minute.
Hot coffee, brown sugar, whipped cream and a good Irish whiskey can be used to make Irish Coffee.
Warm cream, honey, and scotch can be used to make Atholl Brose. Insert a sachet of milled oats into the pan with the cream for extra flavor.