This only works if you're 33 and under, I realize.
For me it was John Ngugi and Zola Budd. Ngugi was a great runner. Every single runner on there was a great one, no flukes ever win World Cross. The only one I've never really heard of since '75 is some guy named Bekele.
I mean, of course, Bekele Debele, who won in '83.
http://www.gbrathletics.com/ic/xc.htm
That year, 1986, was also the first year that the Kenyan men ever won the team championship. They won for every year of my childhood, next losing in 2004.