I love that Portland is one of the most environmentally progressive cities in the country and I think if they make serious progress with this ban, it could lead lots of other cities to following suit.
Part of the article mentions the plastic bag as something that will last thousands of years but only be used once. I think, even if some cities don't want to impose actual bans or fees on bags, there should be a serious incentive to REuse the bags – at least the ones that didn't rip. How many people take all their plastic bags, wad them up and shove them in a cabinet? They'll survive another trip to the store (unless they were forced to hold cans the first time around.)
I can just imagine, in my so-behind-we're-going-backwards city, the people in slippers and glorified pajamas at Wal-Mart complaining about having to bring their own plastic or cloth bags. I can hear the "unfair" cries already. But with the fact that there are probably 5 plastic bags for every 1 person on the planet, I would gladly set up some sort of donation system.
Anyway, I hope Portland can set a precedent and influence more cities to follow suit in some sort of plastic bag ban.