That's definitely something I forgot to mention. Seattle doesn't have all that much crime for a city of this size (mostly petty things, occasional muggings, cars being broken into, people asking if you are "lookin" or "holdin" etc), but the homeless and "crazy bum" (I separate the two) populations are pretty strong. It's one of those things, like the rain, that you just accept over time.
It's not something you really become too much of a bleeding heart over, because for every 1 legitimate, hard-times, homeless person there is...there's probably 5 scammers that have a house but just dress in bum-wear to make bank (and they do make bank).
I've seen some nasty, annoying bums...and some truly kind and endearing bums. It depends. I've never felt unsafe in Seattle after 10pm even in the heart of downtown. Then again, I probably look like one of the riffraff myself.
I've heard great things about Portland, even though I'm in Vermont which is on the other side and similar to that. I'm originally from Ohio, though (long story). I know a guy who's a comic book illustrator who lived in Burlington, VT and has relocated to Portland over a year ago and enjoys the place. Most of what you described is similar to my experiences here.
EDIT: and an old friend of mine from Ohio's been seriously considering moving to Portland by a year or so for personal and professional reasons.
Of course, I would like to see more of the creative scene to explode more often. Fortunately, there's always Montreal as above, and Boston so below.
I've been dying to at least visit Portland, if not live there. Heard so many good things about it. I'm envious of the people posted here saying they are going to move there.
I still have time... I'm young. But god dammit, I'm jealous! : O