[Handro]

I don't think Chicago and New York are similar at all, except for "skyscrapers." But even those are different in each city (NY tall/skinny, Chicago shorter/wide). New York has no counterpart in North America, IMO. Someone said Chicago and Toronto and I think that's a good one.

Boston/SF maybe, that's an interesting comparison. Clearly different cities with different building styles, but similar feelings of density distribution and demographics (as far as class and education go).

I'd hesitantly compare Cincinnati and Baltimore.

The great lakes cities are probably more alike than different--Milwaukee, Cleveland, Buffalo all have lots of similarities.