Oh, and from West Seattle, if you don't feel like dealing with the bridges, you can take the very cute little pedestrian/bike ferry from West Seattle to Seattle.
(you can also take the ferry home again)
No cars allowed on the West Seattle ferry, just bikes and pedestrians. One of my coworkers was doing it every day while she worked down town, she really liked it. I've never ridden it, so I can't tell you much about it personally.
"If Americans want to live the American Dream, they should go to Denmark." - Richard Wilkinson