I go in phases, but Citadelle Gin is my go-to for martinis now, used to prefer Bombay Sapphire but I like the Citadelle better, and it's less $$ to boot (going up lately, though). This is my most common liquor to drink, but not for the last few months.
When I'm not having gin martinis (so the last few months), I vary between Jim Beam Black and Evan Williams bourbons - usually on rocks, sometimes add a splash of H2O.
I mix it up w/ Scotches - when out I usually order Dewars, at home I drink Cutty Sark and dip into Laphroig and Dalmore on occasion, I like the Glenlivet 12, too.
I drink Bushmills when I drink Irish whiskey. I want to try more Irish whiskeys this year.
Rarely drink vodka, but I find that Taaka Platinum (in the blue bottle) is a fantastic off-brand that we have found we prefer over much much loftier names (did our own blind tastings) - the kind of vodka that's a great "well" vodka for the house when mixing Bloody Marys, vodka cranberrys and the like, but also tastes great on rocks or in vodka martinis. This will impress even vodka snobs. I do want to try Cold River vodka, though, it's a potato vodka from Maine I've been hearing about.
I used to be a big time Southern Comfort drinker, when I was 21 ish. Half pints for fishing trips (5 AM drinking!), shots before nights out, concerts, bonfires, etc. Good solid go-to drink, I still order one occasionally when out. SWMBO hates it, though, but I usually keep the 100 proof in stock, sometimes also the 87.