Here's some GTFS feeds: King County Metro - http://www.gtfs-data-exchange.com/agency/king-county-metro-t... the above feed includes King County Metro buses, Seattle Streetcar (the SLUT cwe mentioned), Sound Transit Link light rail, and some Sound Transit express regional buses.

Sound Transit (buses and Link Light Rail) - http://www.gtfs-data-exchange.com/agency/sound-transit/

Community Transit (Snohomish County, lots of bus routes from up there down into downtown Seattle) - http://www.gtfs-data-exchange.com/agency/community-transit/