I commute by bike in Atlanta. Few of us make it to the point where heart disease or lung cancer is a real issue. Soccer moms chatting on cell phones will be the end of me.
Recently I read that something like 70+% of all men past a certain age had nascent cancers when they died, regardless of whether cancer killed them. To me that leaves cancer my #1 fear above all others (ignoring "events", like being hit by a car), since our generation is going to live much longer, and thus be hit by even more cancer.