Christopher Reeve, obviously. Anyone who says otherwise is mentally ill.
Please, it really depends on what you identify Supes as. For the modern age (80's plus) Supes is portrayed as extremely well built. Chris Reeve while a good looking man, with a nice frame isn't defined to any real degree. He really doesn't look that much like the Superman of his day (body wise)
While going back to the 30-50's Superman had a body shape that Reeve's doesn't even come close to, as its far more bulky (though not heavily defined at all). And George really came very close to that body shape.
So I could never say Chris Reeve really fit the look of Superman for his time.