I remember it as well. We had just moved to CA in 1980. I remember shortly before his death, driving by a pizza place (of all places). They had a banner outside that read: "John Lennon Is 40." Don't remember when is birthday was, but it was shortly after that he was killed.
Definitely a talented singer/songwriter who's music fortunately will remain with us forever. If he were alive today, I would imagine he'd be releasing "Give Peace A Chance" once again.
TIS