I don't think he meant that kind of cocktail. More along the lines of classic drinks made from any combination of liquors, liqueurs, bitters, and citrus. Think an old fashioned.
Some recommendations. These are serious spirits that meet "the good stuff" category, though not necessarily the absolute top end.
Bourbon: Buffalo Trace or Eagle Rare. Between those two (and Evan Williams Single Barrel Vintage), you're going to get the best values in Whiskey.
Smoky Scotch: Laphroig 10y (I actually prefer it over their older expressions). Some people love this stuff, some hate it, and there are few in between. If you like it, you'll love it. If you don't, you'll hate it.
Boring Scotch: GlenAnything. (Can you tell where I stand on the previous question?)
Don't know enough about brandy to comment. Seems like you're already doing alright on the Cognac front. Basically, any of the well known brands should be good.
Gin: Basically with Gin, since it's not aged, once you're above a certain base level in quality, it's all about the flavor profile, and everything is about equally good. I'm a fan of Brokers at the moment. Beefeater is a classic, as are both Bombays (regular and Sapphire). There are a lot of craft gins these days, both in traditional and unorthodox camps. Death's Door, out of Madison, is a very good one in the traditional camp. Bluecoat out of Philly is another traditional craft one that should be easy enough for you to find. Sidenote: Most people don't drink gin straight, it's usually used in cocktails, since the sharpness of the flavors seems to be best contrasted against other things. Then again, a lot of people drink "Martinis" that are nothing but chilled gin with an olive, so...
Vodka: High end vodka is a marketer's wet dream. It's really no different from the stuff at the $15 pricepoint. Stay away.
Tequila: I know nothing. Just make sure it's 100% agave, you should do alright. Silver or Reposado for mixing, Anjeos for sipping.
Rum: Barbancourt is a favorite. The older, the better, though the 8y is probably the minimum I would go for nice sipping. But there are lots of nice sipping rums out there for reasonable prices.