Bob is a power chewer too, anything and everything! He has gotten better now he is older but Kongs and konglike rubber toys are the only things I dare leave him with still!
I don`t know about nylabones, I have never tried him with one, though the ones that CincysMom has written about sound good, I may get one for Bob and see how he gets on.
I can recommend the Kong however, Bob has had his black one for around three years now and it is still ok. It also has a plus in that it can be filled with all sorts of stuff and keep a dog occupied for quite a while. (though Bob seems to empty it in record time now, practice makes perfect I suppose!! LoL)

Bob hasn`t chewed up any music CDs but he did chew up the CD software disk for my scanner..grrrrr