Where will you be staying, north, central, or south of town? Will you be skiing on the weekend?
North of town either Baker or Stevens would be an obvious choice. At that time of year if the conditions are sketchy Stevens usually has the better snow. If they are OK it doesn't really matter, but the drive to Stevens is a little less of a challenge. Baker takes longer as well.
Center of town, either Stevens or Crystal, leaning toward Crystal depending on conditions. Crystal is larger and has more to choose from but Stevens sometimes has better snow.
Alpental is great too and you might like to try night skiing there. It's about 45-50 minutes from downtown Seattle and is a good after-work destination. It is at a low elevation even by our standards so it can be a problem sometimes. You'll have plenty of base snow, however.
Having said all that, if you are planning on skiing on Saturday or Sunday then go to Baker. Period. The other areas are mobbed in January and February on those days. Baker has plenty of folks, but nothing like the areas closer to Seattle.
If you like long drives you could try Mission Ridge, but I don't think it would be worth your time on a first trip. You would have to drive within spitting distance of Alpental or right through the parking area for Stevens to get there.