most bang for the buck...i'd say vail. it's fucking enormous. the front side of the mountain is meh, but the back bowls are ridiculous on a pow day. it's definitely not the gnarliest terrain, but still has some decent stuff...some cliffs, trees, etc. i'm kinda lazy, so the lift accessible bowls are a lot of fun.
if you're only looking to ride park, hit key or breck. breck has better terrain if you want a dope ass park+the ability to ski some chutes, etc., but the lift lines can be a bit ridonkulous if you aren't at the right place at the right times.
or there's always cb, steamboat, etc. you've got so many options in CO. it really depends on what you want to do.