The bone I keep going back to
Split Elk Antlers
They're pricey, but they're worth it.
That's right - the price tag reads $35.83 - and that's just for ONE. But this bone lasts a long time and I don't get sick of it like I do with some other bones (note: the prices are different depending on the size, but $25 - $30 seems to be the average).
When Mom and Dad won't give me any of their food, or I'm bored around the house, I take my frustrations out on this bone. There's something about the middle part, the marrow, that's extra delicioso and gives my teeth a good scrubbing. I probably chew on it about once every couple of days, so the bone lasts about 5 - 6 months (Mom throws them out when they turn into stubs).
Hint: Since the bones are so porous, you can soak the bones in chicken or beef broth to make them extra tasty! Fill a bowl with enough broth to just cover the bone and let it soak for 24 hours, then let it completely dry, and voila!
Mom buys these at a local SF boutique pet store but you can also find them online:
Summit Antler Chews