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@hummus and carrots, Where in the country are you? Do you have a cuisine type distinctive to your region?
In Texas, I might do chicken fried steak
In Louisiana, crawfish.
In Maryland, crabs.
See where I'm going?

I think the South offers a lot of dishses that people would often associate with "All-American."
I'd have fun with it and make hushpuppies and fried okra for an appetizer. Fried Chicken with Waffles, ribs, or pulled pork for a main dish. Maybe some individual fried apple pies or pecan pie for dessert? Don't forget buttermilk biscuits!
Or generally you could make-
Green Bean Casserole
Beer-can chicken
New England Clam chowder
Po-boys
Chicago style hot dogs
Ambrosia salad

I'd recommend things you don't really see across the pond: bisquits, sweet potato casserole, okra (OK, it's African in origin and available in B and F but its modern ties are to Southern cooking, just don't boil it into a slimy mess), Texas-style BBQ (advertise it as so), corn dogs (this slayed them in Belgium 3 years running; I have NO idea why); American fruit pies; American cakes (much sweeter than European style pastries and half of them love them while half hate them); fried pork; American variants on shellfish recipes (shellfish very expensive across the pond); yams; anything with pecans, including salads. Just don't tell them that Americans speak 178 languages and cook great, authentic food from just about every region in the world and you have no idea what "All-American" really means in such a place of culinary variety today. They wouldn't understand and would get their feelings hurt about wherever they are coming from!

And of course, American wine and micro-beer to match.

Not sure where "across the pond" is, but if they're British, save the heartache and skip the steak. In my experience, most Brits still want their meat cooked well done. Meatloaf could be a good option instead.

What about chicken pot pie?

My immediate thought for an app was a wedge salad. Something about it feels very Americana to me.

Appetizer: Bacon wrapped Shrimp, cooked on the grill

Dinner: Fried Chicken, mashed potatoes or potato salad, corn or a green veggie & salad loaded with fresh veggies and some fruit (like apples & red grapes).

Dessert: Apple Pie and Vanilla Ice Cream

I was thinking Corn Chowder
Meatloaf with garlic and cheddar mashed potatoes
Popovers or biscuits
Deep dish apple crumb pie w Vanilla bean

@Michigander - when I came home from a summer in Mongolia, American grocery stores were a sight for sore eyes (and I wan't even REALLY into cooking at that point).

I like the bacon-wrapped shrimp+grill idea. You could also do spinach and artichoke-style dip or cold veggie 'pizza' (crescent roll dogh, cream cheese + ranch 'sauce', topped with veggies and chilled) for an appetizer as well. I'm on board with the burger idea and beercan chicken too, for the record. Grilled potato/sweet potato wedges plus some salad and grilled veggies would accent nicely.

And what about cheesecake or chocolate chip cookies for dessert?

App: Buffalo wings with celery & carrot sticks & ranch dressing
Main Course: Meatloaf basted with BBQ Sauce, garlic smashed potatoes, green bean casserole (YES, that kind...very American!), honey/ginger glazed carrots
Dessert: Apple pie w/maple walnut ice cream or strawberry shortcake or good old fashioned Devil's Food cake with fudgy frosting

Depends on how upscale or casual.

When I think of American food, I think of:
- nachos w/ chili, cheese, japalenos
- awesome hamburgers w/ skinnier, skin-on fries or potato chips
- apple pie
- rootbeer

Or incorporate all that it is to eat American and include a variety of regional cooking from the:
- northwest - smoked salmon appetizer... I can't think of anything else :P
- west/Hawaii - essentially something Asian or Pacific Rim -- seared ahi, sorbet of some kind, fruits, or aperitif.
- northeast - deli style something like a knish or New England stuff like lobster rolls or NE clam chowdah
- southwest - while it pains me to suggest it since I don't care for Tex-Mex...side of black beans or something
- midwest - potatoes, corn (though not in season), squash, cranberries, etc. side
- south - fried chicken, greens, sweet potato pie, key lime pie

Not saying to make them all, just throwing out ideas. :)

Perky has it just right. If I tweaked anything, I might stuff the shrimp with a little cream cheese inside a jalapeno, then wrap in bacon and grill.

For green veg, my vote is green beans braised with bacon and garlic.

If you are looking for something almost exotically American (they have fried chicken all over, after all), then I'd go all out with a seafood gumbo. I served it to my French in laws and they were very impressed.