I thought a proper American breakfast was eggs, maybe with a side of bacon, ham or sausage. Most of this stuff is what I'd call a "Continental Breakfast".
I think the obvious difference for me though when I was travelling around the USA was not breakfast at home, but the ease with which you can get (and the consequent quality of) breakfast "on the go".
Other than McDonalds (of course) and a handful of restaurants, I can't think of anywhere here to get breakfast, or something breakfasty, except cafés/sandwich shops that'll be selling the same things they will for the rest of the day. Maybe that's just the different view you get living vs. touring around on holiday, though.