I'm not sure it's a black-or-white, either/or thing.
At least one study has suggested that in places where pornography is readily accessible, there's less sexual violence. I tend to think that's a good thing.
Likewise, it often seems that where, as a culture, we decide to simply fold our arms, scowl, and intone, "Decent people don't do those things," we inevitably reap the result of our decision to willfully disregard reality (see also: The Drug War, abstinence-only sexual education, Prohibition...)
And like some of those areas, I tend to feel we're better off with a certain degree of regulation (e.g., drug and STD screening and some laws to prevent coercive practices) than banning.
Also, this may be one of the few ways in which the Internet, weirdly enough, is actually something of a unifying influence. You know that weird thing you've always wanted to do with the blueberry pie filling and the Troll doll?... There's someone out there with a page full of photographs.
It sounds ridiculous, I know, but I genuinely tend to feel it's better when people don't have to sit alone in their rooms and think that they're so alien and strange that there couldn't possibly be anyone else on Earth like them.
All that said, we're also starting to see certain cultures emerging in which sexual desire isn't something you turn to other people to fulfill. For some people, possibly even an increasing number of people, pornography is becoming an enabler of failure to develop social and emotional skills and possibly pathologically self-destructive behavior.
I'm not saying that everyone who enjoys pornography is damaged, not by a long shot. For some people, pornography is clearly part of a robust and healthy sexuality. But I do think it's becoming easier to use pornography in unhealthy ways, and there's certainly nothing in pornography itself to prevent that.