My gradfather is in his 80's, the other one died in an accident. My step-grandfather was 75ish when he died of stomach cancer, and he used to smoke over a pack of pipe tobacco a day.
My grandmother is in her 80's too, the other one died of complications following a heart attack (her first ever) when she was 90.
so yeah, if I take decent care of myself (and quit smoking), and don't get into any serious accidents, I got the genes to take me though at least another 50 years.