Only right answer here is "Depends where you are."
You wouldnt drink the same thing at a wedding bar as you would at the sports bar. You wouldnt drink the same thing at a night club bar as you would at a "buy me drinky bar" or a strip bar.
-Sports bar/trashy casual places I would usually go for a light beer. Miller Lite, Bud Light, Coors Light. Easy on the calories. Easy on the wallet. These types of scenarios would usually be dominated by guys anyway, but just in case you do see "eligibles" there, hot servers/bartenders, or, whatever, you dont want to look like the only sober person in there. You're probably there to have fun anyway with "the boys" and you probably had to drive yourself too.
-General Nightclub scene I would usually go for a Vodka tonic. Beers take too long to drink, you're probably moving around a bit and dont want to be weighed down by heavy beer. You also dont want to have to take a piss every 5 mins because there are probably drunks fighting/passed out/vomit on the floor which you have to deal with when you go to the bathroom. If you end up buying a girl a drink and shes there when you order, get some top shelf for the both of you. If shes not there, get "well" or "house" drinks.
-Private Nightclub scene. Bottle service. Since a bottle of beer will cost you $10 or more, and a single shot will cost you $10 or more, might as well get a bottle (or 3) on ice. It not only looks and feels legit for you, but its even better for her. Especially if random people pass by the cabana or booth that you're in. (Pro Tip: Get the most visible one if you're going to reserve. Best bang for your buck. The best ones are the ones with only ropes between you and everyone else. Paying for a totally private booth/cabana is a lose/lose for you. No visibility.
-Weddings. Fine dining. You're trying to be social. The only time you're allowed to be drunk at a wedding is if its your own. Key thing here is to fit in with whatever everyone else is drinking. If its wine, know a little, about wines. If its champagne, its champagne.
-Strip bar/Drinky bar I usually just take shots and drink beer at the same time. The shots add up, especially if its for one of the employees, so drinking beer helps offset the cost since they wont drink beer. Drink a beer or two, buy them and yourself a shot, repeat.
My first post. Hope it was a good one.