If you want something solid, that does the trick, and doesn't taste overwhelmingly like something you pay $100 for at the perfume counter, try a simple gin and tonic. The best gin is probably Bombay Sapphire.
There are always the vodkas... a college staple, nowadays... Stolichnaya's good, but Grey Goose is the best... there are some newfangled vodkas (Skyy) which have hints of lime, orange, strawberry, etc. flavoring, which may suit your taste. Purists would obviously have none of that. Have it with a tonic or orange juice or a variety of other mixes... I like mine in straight shots.
Classic tequila shot, lime and salt. Always an excellent punctuation point during a night of drinking. Jose Cuervo will do. Nothing more need be said.
A light liquor is Bailey's Irish Cream... I enjoy mine 1-part milk, 3-parts B's I.C. It's more of a "I don't bloody care what anyone thinks it tastes like something from bloody Starbucks and I LIKE it and NO I'm not a fucking alcoholic.... where's that bloody bottle? What? It's finished? Already? Damn thing runs out quicker than excuses..."-drink than a real dyed-in-the-wool liquor.
Others... a jack and coke... Jack Daniels, a whiskey, and coca-cola... whiskeys and their cousin bourbons are an acquired taste, though... I doubt a beer drinker would take quickly to them.
With many of these drinks there are many ways to have them... straight or on-the-rocks is always an option, but I recommend starting with mixes first... particularly when it comes to whiskeys, bourbons, cognacs...
This isn't a very original or comprehensive list... but it's a start... and it works for me!
The other option is to just to just look behind the bartender, check out the bottles, don't be shy to ask a couple of questions (bartenders, when not very busy, are usually good talkers and everyone likes to talk about his/her own profession) and ask for a recommendation. EXPAND YOUR HORIZONS but make sure you're sober enough to get back home.