When I was in highschool in the late 90s we used to use "Chad" to refer to the preppy tennis-player and fratboy types. Only we didn't use it as a noun but more as an actual name. In other words, we wouldn't say "That guy with his sweater arms tied over his shoulders is a Chad" but we would say "check out Chad over there with his monogrammed money clip." It was definitely a class thing.