None.
It’s impossible because we all have different definitions of “unfit for consumption”. Some people would call Trump’s campaign platform a hate crime. Others would call a woman with her face uncovered “pornographic”. Some places have some interesting ideas of what is considered “subversive”. Hell, there are some within our own country that consider anything other than theocratic anarcho-capitalism to be High Treason.
As disappointing as it is, I would say that the US is among the closest simply because freedom of speech is part of our nation’s constitution. Any place that has a more sanitary internet that what we have here usually has enough restrictions to not qualify as “free speech”. Yet many would (and do) argue that even we are unfree due to censorship or monitoring. Reporters Without Borders lists the US as an “Enemy of the internet” due to it’s pervasive surveillance while things like the DCMA and attempts at SOPA, PIPA, and related legislature are taken by some as an affront to not only our constitutional rights, but our human rights as well.
Now, if you want places where it takes the least effort for an end-user to avoid exposure to “unfit for consumption” content, you’re talking places like Iran, China and the Middle East that give fewer-than-zero shits about free speech. The internet is nice and safe there.
Freedom is a double-edged sword. You can’t have freedom and restrictions; it’s either/or. Either you have freedom of speech or you deprive others of it for your own comfort. You can’t have a free internet without risking someone having an opinion you find offensive, and you can’t restrict the internet without taking away someone else’s freedom.
You may be interested in what Freedom House has to say about how restrictive the internet is around the world.
@ragingloli Iceland.