I'm Canadian so what I'll have to say probably doesn't count for much (until Steven Harper decides to troll the masses and to whip up SOPA's Canuck clone), but I imagine SOPA won't have too much of an effect, even in the US. Going around despite DNS blocking is quite possible, and the targeted sites that'll have some sort political and public acumen are going to be up in arms about the bill.
I just don't see Google and YouTube kowtowing to shit like this, even if I'm pretty sure Microsoft is already bent over, fully lubed and ready to take it. Either the Silicon Valley falls apart and the IT investors realize they made a derp even as the American economy goes further down the crapper - or hacktivism gets cranked up to eleven and we start hearing about various pseudo-legal ways to bypass the bill. I'm fully expecting Anonymous to be willing and able to massively troll with Washington, just to get the message across.
Unfortunately, the bill's backed by folks that don't know the first thing about computers, the infrastructure of networks or the Internet in general. They're seeing us as a bunch of tryhards, whining little Liberals who've been raised in a system of systematic and accepted theft. Or something like that. So, well, they're feeling all righteous and shit.
Any way the wind's gonna blow, things are going to change. That much is obvious. The best case is the entertainment majors realizing they have no sway over the Internet no matter how hard they try, while the worst involves the US virtual shores turning into some sort of policed state. Then they'll keep saying they're not like China, even if they block sites arbitrarily judged as infringing SOPA.
Then, of course, the Deep Web becomes more crowded, or private networks begin to emerge on US soil.