and now they have a lrt system they are continually adding to, to go along with their modern streetcar in tacoma, modern streetcar at south lake union, and their historic streetcar. they are also adding to those systems currently. they had plans for a massive expansion of the monorail system not that long ago, and after canning the idea, they are now full speed ahead with lrt - and passing the twin cities by at warp speed.
http://en.wikipedia.org/wiki/Seattle_Monorail_Project
Sorry to nitpick, but the historic streetcar in Seattle has been "indefinitely" out since 2006. The are, however, building a First Street streetcar currently. Of course King county voters voted to tax themselves for ST2, which funded the LRT expansion. There are still talks about building a West Seattle to Ballard monorail, because the new Alaskan Way Tunnel is making that rail connection tough.
Back to the subject, if your going to do Monorail why not do PRT?