Okay:
There's no such thing as a classic "American City" - there's the northeast metropoli, Boston, Philly and Baltimore that have a very similar history and some shared characteristics (New York is a league onto itself). Baltimore, Philly and Boston all have old cities near the water, while the business centre moved inland, with very historic building types the Americans like to play with like post-Colonial Georgian, Greek Revival, then Neo-Gothic, Art Deco, and everything up to now.
Then there's Washington, perhaps the Central European style capital (and Mexico City really has a Euro-American thing as well), surrounded by a graham cracker of small charming towns absorbed into suburbia and outposts of urbanity in Virginia and Maryland.
Then there's the classic Midwest City- I'd put Detroit, Cleveland, St. Louis and even Buffalo and others in this group, with the boom between 1880 and 1945, with some modern and po-mo growth but on a relative or absolute decline (with really troubled neighbourhoods) since the 1960s, surrounded by low density suburbs. Chicago belongs, but as a super-city, has broke through this classification as it never declined, but continued to be a magnet.
Then there's the West Coast cities, all very distinctive from each other (LA vs. SF vs. Portland, etc). And finally there's the Sunbelt/New South cities that boomed much later - Phoenix, Dallas, Houston, Atlanta, even Las Vegas. Denver fits in this class, but is influenced by the Midwest archetype.
There's certainly regional variations. In Canada, the cities have the same basics: St. John's and Halifax do have some similarities beyond geography, both old British ports and dominant in their region. Quebec City is a classic Eurocolonial town with wonderful setting, but surrounded by horrible sprawl that would fit into deep New Jersey.
Montreal has an East Coast US City style - a very dense inner core, with a central historical district with a wandering downtown that preserved a lot of the historic core (think Boston or Philly) but has the civic infrastructure too of a big US East Coast city - lots of highways everywhere, a large subway, and architecturally and even socially has some historical semblence to an American city. But the unique culture, and the added "Canadianness" (denser suburbs, with the West Island looking a lot like Ontario suburbs), a more tolerant and liberal society, the wonderful cultural history and charm and a certain je ne c'est quoi, make it different in so many ways.
Toronto is interesting because it blends the rust belt/MidWest of the US (though without the decline, so like Chicago), with a bit of East Coast early history and attitude, and a Central/Eastern European suburban model with all the rental towers.
Winnipeg has a lot of semblance to a St. Louis/Kansas City type Midwest City in form and demographic structure, though on a smaller scale, but has that "Canadian" downtown feel that Hipster Duck alludes to. Calgary has the sunbelt thing going for it, very much like Denver, with some Canadian and Midwest influence, and Vancouver has that West Coast variety going for it.
