I'm a Minneapolis native who now lives in Portland.
My ranking would be:
I think the economy in MN is more stable than it is in PA or OR. It's possible to live on the edge of the burbs, and while the homeschooling laws aren't perfect, they're doable (I know several people who've homeschooled there). It's got snow. Good park systems. Lakes.
I vote for Pittsburgh for several reasons. Cost of living is LOW, mostly because housing is cheap. I suspect it's very much like Buffalo, NY where I lived for 2 years. I found the people friendly, the housing very very reasonable, and it a fine place to live, IF you have a job. The economy
isn't great, but I think it's getting better in Pittsburgh. The homeschooling laws are difficult, but could be worked with.
Portland is my third choice. If not for cost of living and the incredibly unstable economy, it would be higher. It's a very crunchy city/region. But housing prices are HIGH. Higher than in MN, TX, or PA. The state still hasn't come to the realization that it's no longer an fishing/agricultural/logging based economy, and so maybe spending money on infrastructure and education might be a good idea. We get these incredible boom and bust cycles. And when it busts here, it really busts.
Austin, I can't comment on. Other than who would want to live in that heat? The city itself is relatively liberal, but the state itself is not. I have a colleague who moved to PDX from Austin precisely because of this.
Chicago is a huge city. The cost of living is sky high. Ugh, is about all I can say.
But honestly, I wouldn't move ANYWHERE without a job and a thorough calculation of whether we could make it there. This is a decent cost of living calculator, and I'm sure there are others: http://www.bestplaces.net/col/