Also consider the Npost.com events, Saturday House, Startup Drinks (seattle.startupdrinks.com), Andy Sack's Open Coffee, the East Side and Six Hour Startup events.
Dorkbot isn't super useful for startups, but it's great if you just want to meet a bunch of interesting nerds.
If you want startups, join the Seattle Tech Startups mailing list (Google it), and you'll have more than enough events and information. There's a monthly meeting, a weekly breakfast, pub crawls, and tons more.