This thread has been a long time coming, as far as I'm concerned, but [MENTION=6]zitothebrave[/MENTION]'s comments—to some of which I will respond below as a first foray into this all-important subject—finally spurred me to action.
I love gin—but I may be one or both of those things.
Not hard for me: I make enough cocktails that I almost always have fresh citrus on-hand. Your gimlet recipe's also missing 0.25 ounces simple-syrup.
You're making it super pear-shaped with that pineapple juice and club soda; you just need: 2 oz tequila (I like Espolón, but Camarena is good enough and super cheap), 0.5 oz yellow chartreuse, 0.75 oz lemon juice, 0.5 oz simple-syrup; shake, strain, dribble a couple drops of rose-water, then slightly stir.
The crème de violette. A standard, proper Aviation shouldn't have grenadine; it should be: 1.75-2.0 oz gin, 0.5 oz lemon juice, scant 0.5 oz maraschino liqueur, shaken, strained into a coupe, then finished with 0.25 oz crème de violette. Of course, that's if you're using Rothman & Winter; I greatly prefer the Tempus Fugit Liqueur de Violettes, so I use about 0.5 oz of the violette and cut the maraschino a bit more.
My preferred formulation that I mentioned (which is sourced from David Wondrich's Imbibe) contains 2 oz rye, 1 oz red vermouth (I love Noilly-Prat, but Cinzano is entirely serviceable), a scant bar-spoon of maraschino liqueur, a dash of absinthe, and two dashes Angostura—stirred, naturally, and served in a chilled glass. But you're right: there are countless Manhattan variations, and if I'm substituting a quinquina like Byrrh or Bonal for vermouth then I'm more likely to use a straight 2:1 or even 1:1 mix, with a lesser dash of Angostura.
I don't drink cocktails because they're trendy; I drink them because they're tasty.
False. And damn un-American of you.
A love a good rye and soda (as in fizzy water), either mixed or side-by-side.
You shouldn't. That's why you learn your brands.
Plenty of preeminent and primordial cocktails were developed well before the Eighteen Amendment; in a lot of ways, the latter-half of the nineteenth century in the US was the first great cocktail era. Moreover: gin is an awesome spirit, with a great history, and very good gins were cultivated and consumed outside the US before, during, and after Prohibition.