The only Chad I've ever known was a kid I had a HUGE crush on when I was maybe 14. He fit pretty much all the stereotypes mentioned (blond, WASP, jerk) but he wasn't a jock, more of a semi-geek who just happened to be cute. I knew him from a drama group I was in and performed plays with.
The name is a bad association for me. I was the most awkward teen girl ever -not only socially, but I was a scrawny thing with Coke-bottle glasses, bad hair and acne, the whole nine yards. I tried to "ask him out" but got rejected. The VERY NEXT DAY he decided to go with the most outgoing, obnoxious, overdeveloped girl in the group. I was very intimidated by this girl and she and her friends constantly bullied me. I was so upset. I am 30 and still haven't forgotten this.
So yeah, Chad sucks.