For you real data junkies and for a broader look at Oregon than just Portland, here, once again, is the Office of Federal Housing Enterprise Oversight's House Price Index (HPI). The Q1 08 results are in and here is what it looks like:
It is pretty remarkable how different a picture the Case-Shiller and the OFHEO data paint. Panic or not? Remember, these data (OFHEO) contain more houses (not just Portland), but only conventional loans (so no high end houses).