Never been to Colorado but Washington can have some pretty good skiing, although you might have to put yourself through a few rainstorms to get the pow. Summit at snoqualmie is the most well known resort due to its proximity to the Seattle area. On Friday nights when all the middle schoolers come up the lift lines are 30 mins for maybe 1000 feet of vertical, never go on Fridays. However it also has smaller side "mountains", don't really know what to call them, fittingly named East and West, that are much less crowded. East does not offer night skiing. West is largely shit. East however is not. Of the three areas go here if it dumps. I think it only has two or three chairs, but we got about a foot in February and I skied about eight runs right onto the lift. Also has some pretty sick tree skiing. Alpental is also run by Snoqualmie and is a short ten minute drive away. Far less popular, this may due to quality of chairs, it accesses much more and much more advanced terrain. If you are really good skier this is your go to mountain if you live in Seattle.
Crystal Mountain is about a two hour drive from Seattle but unlike the Summit at Snoqualmie if is actually a mountain. Has a bunch of really nice lifts and if you want to walk a bit, some pretty nice bowl skiing. Due to its size you can usually find some pretty empty lift lines upper mountain.
I've never been to Stevens or Baker but if you are looking for really good skiing go to Baker, if gets a shit ton of pow, in fact I think it has the world record for snowfall in a season, and a lot of ski movie parts or just short segments are shot there. Baker has the best big mountain skiing especially if you can walk or tour.
Looking at your question again I realize I forgot to answer the park part, both summit central and crystal have parks, I think central's is better, but not too sure. Welcome to the city of rain.