Maybe it's because I'm from a younger generation, but I think that anything MORE than four rings is too much. No matter where I am in the house, I can get to the phone by the 4th ring, and I have only one phone in the house.
Then again, I don't have the compulsion to answer the phone that seems to plague everyone else in civilization. I answer when I feel like it and let it ring when I don't. After all, the phone is there for my convenience, not everyone else's. And especially not telemarketers. If I decide not to answer, anything past the fourth ring is just annoying. Ten is downright rude. (And to be a guest in someone's house and they stop a conversation to answer the phone seems really rude to me, too).
At work OTOH, I always try to answer between the second and third rings