Good strong dog toys?

Im looking for toys for my nearly 9 month old pup. They need to be strong as hes a dab hand at chewing. What does your dog love to play with?
At the moment he has a kong, nylabones (he chews these quite quickly) and a tennis ball sized ball , looking for things to keep him occupied and that i can play with him in the house

Mine are aweful chewers and iv found very few toys that last with them. I have XL kongs which are brilliant, not had any problem with them and they've had them for about 9months with no sign of wear.
They also LOVE ruff and tuff toys [from P@H] which are quite hardy. As far as tennis balls go, they are lucky to last a week, but the kong airballs, with the squeek, are a firm favourite.

Planet Dog Orbees are good. they're expensive, but really good and I have read somewhere they have a lifetime guarantee on them (the reason why P@H stopped selling them)