For anyone flying in and out of Seattle, add Alpental to that list; it's the closest to Seattle and (per King Grump) has terrain like Taos.
All are easy day trips from Seattle. Here's a suggestion: Day 1, take your pick of Crystal, Alpental or Stevens. Day 2, get an early start in the day, ski Baker and then it's a 3 1/2 drive to Whistler.
This works particularly well for folks flying in and out of Seattle or those driving from Oregon and California. All of these places are strung along I-5 which leads you right up to where you will cross the Canadian border. While Alpental is an experience all to itself, I think I wouldn't plan on it for a single day to sample Seattle area skiing. It's small and at low elevation, so conditions are good on a lower number of days than at Crystal or Stevens.