I looked through the hiddenwiki, avoided the cp stuff obviously, but I didn't see a ton of content, just random stuff.
I downloaded Tor and ran it in a sandboxed vm, just to see if anything happened, scans, etc. but I didn't see any nefarious activity.
Heard Anonymous injected a root kit in one of the recent Tor betas. Their reason was to check pedos (+1 for anon) but I wonder if that's ALL they'll use it for.
tl:dr Deep web is kinda whatever.