If you build a proper site, it will stand a neg SEO attack.
Even Google has started to address these issues and recently said that links FROM a bad neighborhood will not hurt most sites, but linking TO one will.
I had a customer get hit with 100's of thousands of Russian porn links, I even come on here and made a post asking for guidance.
I was told to disavow the links, and a few other things, but I never did anything, and the site is still as strong as ever.
Google did not send me an unnatural links warning, nothing happened at all. It never hurt the site at all.
I have a theory that Google lets out just enough info to keep IMers chasing the dream, and constantly snatches the run out fro under them, so they keep wasting their time.
Before I would do neg SEO on someone I would do positive SEO for their competitors. Boost up everyone BUT him, and let him stew in that.
There is a guy who stiffed a friend of mine in Austin. He had work done, then did a charge back. My friend and I are in the process of helping everyone on the front page but him.
For the first time I am enjoying watching someone's rankings slide.
It just takes a little extra work as I travel around, find a nice link and send it along.
Doing positive SEO for someone feels a lot better, Karma wise.