As some people tend to say "oh but police should do something against crime" or "just use OpenDNS" I would like to add some points here.
First we have to understand that this is one out of many laws over the last years (e.g. adding of biometric data and RFID chips to passports, logging all telephone/email etc. sessions for 1/2 year, allowance for shooting down hijacked plains etc.) which converted Germany into a police state again. Not so obvious or visual as in times past, but still as dangerous.
Fighting child porn is of course only a cheap argument as one can be sure that opponents can easily be labeled "child molester". Basically the same as we saw with "terrorism" in the recent past (see "patriot act" in US). Given Germany didn't have a terror attack so far, "terrorism" is not a strong enough fear factor / selling point, but "child porn" is great for building consent in order to have people enslave themselfs.
These days I often think about the famous Martin Niemoeller quote:
"In Germany, they came first for the Communists, And I didn't speak up because I wasn't a Communist;
And then they came for the trade unionists, And I didn't speak up because I wasn't a trade unionist;
And then they came for the Jews, And I didn't speak up because I wasn't a Jew;
And then... they came for me... And by that time there was no one left to speak up."
So at the end we are always affected - even if the first shots don't hit us directly.
Once the censorship infrastructure is in place, it is clear that it will also be used to serve the content media. Actually first politicians already acknowledge that - even before the "we do it only to protect the children" law is signed! But it will not stop there and on Wikileaks you can find filter lists of Norway for instance where you can see what stuff they censor. With the current events in Iran we also get a sense of where this can end.
The Internet is too vital for our societies to have politicians or the state mess with it!
PS: Sure OpenDNS might do the trick for the current law. But that's the wrong answer, because it basically is retreating - leaving the big pool of "non IT folks" behind. Also those loopholes will be closed over time or at least it will become suspicious / illegal. Actually that's also a "funny" part of the original version of the censorship law. The idea was that once you visit a web page which is on their list, that you will be forwarded to the state run "stop page". Hits at this "stop page" were planned to be logged and turned over to law enforcement. So in extreme cases you could think about adding a crontab entry to someone's computer ensuring the police to have him visit. Given that the only way to be safe would be to use something like OpenDNS in order to ensure to not hit the stop page. So actually you have to act like one who still wants to access the "child porn" pages in order to be sure to not be suspected of "child porn". Wired isn't it?