Actually, our Sun cannot supernova. It is too small for that. (
cite)
However, if you would like something to worry about, how about
Eta Carinae. It could hypernova
in our lifetime. Since it is only 8,000 light years away, the resulting gamma ray burst would completely sterilize the Earth. Or to look at it another way, because of the distance, it may have already gone hypernova and we are just waiting for the GRB to arrive.