From what I hear from my friends who have been to the US, portions are larger and it's more or less expected you'll take some home.

The only places down here where I have seen huge portions are steak houses, other than places like Sizzler where you pile your plate anyway from the buffet.

I have to say this: it does annoy me how you pay so much at upscale restaurants for so little food. The only place I've seen that doesn't do that is Aria, and it's one of the reasons my fiance and I loved going there.