I've ruined permissions at my home backup drive (it was 75% my fault to be honest). I tried to fix it terminal/unix way but it ended up with something even worser. Broken resource forks, fancy non existing users and permissions... (OMG, my lovely icons collection gone in bits and pieces). Then I was looking for easy solution to get back those zillion files live and proper. And you know what?
The easiest way is to copy your files to FAT32 dive if you have any handy. What will happen: all your permissions will null comparing to HFS+ (but keeping icons, forks, bundles etc intact though).
So the files you will get copied back on HFS drive will be read/write enabled by any party including you. That was exactly my target actually. And don't forget to erase/format your troubled drive just to keep it sane.
This method will of course take a while (as my 500Gb coping back and forth took about one and something hours). But it worked.