In addition to the building permit database, Seattle.gov provides a dataset for historic buildings at:
https://data.seattle.gov/browse?tags=historic+register

Any building in Seattle that is a public housing or multi-family housing inspected for public housing assistance program will have info in this HUD dataset:
http://www.huduser.org/portal/datasets/pis.html

The footprints and building heights are commercially available ($1571) at:
http://market.weogeo.com/datasets/nokia-here-buildings-seattle-wa-metro-region.html

Otherthan that, the best way to get this information free (or near FREE) is to go to the property tax office for King County and see if they provide a electronic copy (e.g., like on a CD) for a fee.

UPDATE: I found some more links on building lot outline in major cities open data. This comes from stackexchange question: http://gis.stackexchange.com/questions/2046/where-can-i-find-building-footprint-data/2050#2050


Chicago: http://data.cityofchicago.org/Government/Boundaries-Buildings/w2v3-isjw

Seattle: http://data.seattle.gov/dataset/2009-Building-Outlines/y7u8-vad7

Bellingham: http://www.cob.org/services/maps/gis/index.aspx

Bloomington: http://bloomington.in.gov/documents/viewDocument.php?document_id=1870

Spokane: http://www.spokanecity.org/services/gis/data/

Kitsap County: http://www.kitsapgov.com/gis/metadata/