Seattle is a very EXPENSIVE city to live in (used to live there). On MSN a few months ago they had a list of the top 10 most overpriced cities to live in, and Seattle was No. 1.
The traffic is indeed pretty bad. Some I-5 traffic jams can mean 2 hours late (though this is rare at Ortho Resident commute hours). It is close to the Cascades, and those are great for skiing in the winter, and hiking/camping in summer if you get time. Puget Sound/San Juans are great for Kyaking. You can row in lake union in the morning, or just do tons of biking on local trails. These are all nice features.
The program is very well known, but is one that many have told me might be better for a fellowship than a residency. I did a month at Harborview, and I found it to be very top heavy, with many cases dominated by fellows, and chiefs 2ndly, but the attendings doing a lot of the cases ("sticky hands" so to speak). 2s get worked real hard at Harborview with q3 in house, and in the ER for the entire 24hrs of call, and not following cases to the OR.
The other rotations are pretty nice, with great sports, very good joints, peds, tumor, Shoulder/Elbow and Hand are top notch, but there are many fellows on all of these as well. Academically very strong. Top notch names for attendings. I think you would get great training, but might still be learning as a chief on some things. And, like many of you have said, you can probably choose any fellowship you want when leaving here.