Go out and experiment, find what you like but here are some suggestions based on category depending on how you are feeling.
"heavy" beer: Dirty Bastard by Founders
"medium" beer: Red Stripe or Killian's Red
"light" beer: Pilsner Urquell
vodka: good but expensive: Grey Goose, less good but cheaper: Svedka, best: Krolewska
vodka special mention: Spiritus, cheap and powerful (about 95% alc) and doesn't taste too bad
vodka mixes with anything, good stuff shouldn't have flavor, classics: Cranberry Juice, lemon-lime soda, Orange Juice, ice and strained into a glass that had been rinsed with vermouth maybe with a twist of lime (Vodka Martini)
spiced rum: Captain Morgan or his cheaper twin brother Admiral Nelson, never found anyone who can taste the difference when given AN when they thought it was CM.
silver rum: Bacardi
"rum" aka coconut flavoring w/alcohol: Malibu, I can't stand it but I can't debate its popularity.
Rum mixes well with cola, especially spiced, it also mixes well with fruit juice. Spiced Rum is also a welcome addition to coffee.
Whiskey: Jameson.
Scotch: Balanced: Oban 14, Glenlivet 12+ Peaty/Smokey: Laphroic
Misc: Southern Comfort, this is not bourbon despite its claim, I don't like the stuff, but like w/malibu, I am the odd man out, people love this stuff.
Mix SoCo with coke, or sprite. If you must mix Jameson, coke, coffee, and oddly enough Mountain Dew (the right proportions make it taste like cream soda). Also Ginger ale and lemon.
Tequila: I like Cuervo Gold, best balance for price/quality I've found imo.
Amazing mixed with Ruby Red Grapefruit Juice.
Gin: Tanqueray
Mix it with citrus juice "punches", squirt, tonic. Like vodka ice, strained into a glass that has been rinsed with vermouth, and a couple of olives. <-Gin Martini
side note: allrecipes.com has some amazing mixed drink recipes.