Big Words is a huge fan of rope bones. It's akin to pleasure incarnate for him. He tosses it around the room, chews on it, chases it, we play hide and find, fetch, tug and more. It is, hands down, his favorite toy.
I've tried other toys -- marrow bones, Kongs, Nylabones, balls. He enjoys them all, but nothing pleases him quite like the rope bone. I also notice a change in his mood (slight, but noticeable for me) when he doesn't have them. Chewing on these is just a huge stress reliever for him.
The downside is, he destroys them like they are nothing. I'm attaching (hopefully) an image of what he managed to do to his most recent one in just a manner of hours. The one in the picture was a Booda Combos Leather & Rope Bone ($14 each at the local PetCo).
$14 is quite steep for something he tears to shreds within days. But I just hate I'd have to deprive him of something he enjoys so much.

Does anyone have recommendations of any similar items that are ultra-durable? I've done some Googling and haven't had much luck.