I don't think buying in Seattle is that unreasonable for a Californian, especially with 20% down and a fixed rate. The lack of a state income tax is quite appealing. I suspect that house prices will come down over time in the NW, but I'm not CERTAIN of it. They might just go sideways for quite some while, which in effect would be going down. I've been expecting the stock market to tank lately, but see that what totally makes sense to me just might not happen.
I suspect that renting a house or condo or whatever is wiser now than buying, and that's what I'm doing (in the Portland area, actually, which has similarities but the market is weaker there). My own plan is to see how bad this summer selling season is, and if it's really bad I'll consider making a lowball offer and see what happens. More likely, I'll wait for the end of the failed 2008 summer selling season.