I think I just read in the news somewhere about a host who accounted for 93% of all the child porn on the internet being shut down. They hosted that shit on the onion side.
That would be the owner of Freedom Hosting I mentioned in the original post. Most of the sites hosted were of a highly illegal nature.
There is a list of all the .onion sites with details of their content on both the wiki and Tor Directory, the latter has reviews. On the wiki page it says which hosts the sites use, if you look at the Freedom ones (FH) you'll see just how nasty some of them were.
I've tried a couple of the tor search engines and they're not very good, they seem to be just word searchers so do a search for 'news' and you will get every single site and instance of the word news in the results.