As I live in the UK, the SOPA and PIPA legislation seems not to affect me, but if whole websites are forced to shut down, it affects everyone.
I appreciate the need to protect copyright and support artists, writers, musicians and others whose work has been pirated and therefore had their livelihoods damaged. However from what I understand, these new laws would go above and beyond this protection.
I rarely watch TV online, and then usually through legal methods, like the BBC iPlayer and 4oD, and I tend to download music legitimally too. But I know people who stream content regularly. That's their business.
Personally I find any form of censorship galling. This is censorship by another name. It would allow a government to decide what was allowed and what wasn't, much in the way we deride other countries' governments for doing so, for regulating what their citizens can and can't access.
My field is in books, that is what I know best. There is a lot of concern about censorship in the literary world; the American Library Association every year publishes a list of the most banned books. Often these are books written for children and young adults.
Instead of letting these readers discover the worlds contained within books, adults decide what is and isn't appropriate and get rid of those they deem harmful. Whenever I think of this I am reminded of Heinrich Heine's quote "There, where one burns books, one in the end burns men". The idea of legislating against a book, or a website, simply because it offends your sensibilities to be unable to control it, is petty and wrong. This kind of policing has no place in our modern world. People are intelligent enough to work out what is right and wrong for themselves. They know what is and isn't acceptable. Stealing from others is wrong, we know this, and while people continue to do so, I'm going to suggest that they're probably the minority.
So, US government, behave like adults should and let people make decisions for themselves. Don't decide to police the internet. It doesn't need your interference.