How I decide where to go: I want a place that a) I've never been before, b) has enough greens that my wife won't get bored, c) has a lot of vertical so I can have nice long runs, d) would be nice if the base elevation wasn't super high, but it's not the end of the world if it is. Your priorities will probably be different than mine. I'll get a list of candidates that fit my criteria from the resort survey issue (each October or so) of Ski Magazine, or by just looking at resort websites, onthesnow.com, etc. Then I'll look at prices. Sometimes I buy lodging and lift tickets together, sometimes separately. I've never bought airfare as part of a package deal, but there's no real reason behind that. That's if I'm flying.
If I'm driving, it's usually just a matter of balancing how far I want to drive versus how big of a hill there is. I live in the middle of corn. 3 hours in the car will get me 400' vertical. 6 hours will get me 800'. 10 hours will get me 1500'. It's a tradeoff. Usually I just go to one of the 400' places and home in the same day.