Without question, for me, it was the theme music to the original adventure game "The 7th Guest".

My guess for all time most 'popular' would be Mario Bros.... and I liked it it as well, a lot.

BUT.. you'll have to forgive me, I'm not a gamer. I doubt I've played ANY video game that came out after about the end of the 90's. So there must be a many out there worthy of mention - I just know of them.

BTW... refresh my memory... Which video game was it that featured "Don't Fear The Reaper?" - JamesJM