Anyways, the closest are Summit at Snoqualmie (around an hour depending on road conditions), and Stevens Pass (1hr20 to 1hr40 depeding on where in seattle you live....the other good mountains are Crystal (about 2 hours), and Mt. Baker (about 2 1/2). Then you've got Mt. Hood which is about 4 1/2 hours south, and Whistler 5 hours north (but you gotta cross the boarder).
My favorties are Stevens Pass, Snoqualmie, and Baker beacause they are all good in completely different ways. Snoqualmie gets pissed on more often than the other mountains because they are only 3,000 ft or so, but they have the best rails, boxes, and pipe. Stevens has great terrain, pow, and variety, but you cant usually count on their park to be spectacular, but its not bad (their jumps are better than snoqualmie's). Baker is for the powder fiends and freeriders, with a pretty shitty park beacuse its frequently getting buried on good seasons. Crystal is for old / rich skiers (they made me buy a leash before they would let me get on the lift), but they have fun freeriding terrain
thats about all i have to say