A Montrealer's perspective...
CANADA
Ottawa: much more beautiful (natural and man-made) than I had expected. Sadly, also more boring despite the modest standards I had set.
Toronto: Much more interesting and lively downtown core than I had expected. Better nightlife. Assertions that the city just extends endlessly and aimlessly inland, however, were easily recognizable.
Kingston: a prettier core than I had imagined.
USA
New York City: I had extremely high expectations. They were met and then some. Truly the center of the universe...
Philadelphia: prettier and more historical neighborhoods than I had imagined. Shopping, eating, drinking all beat my expectations. Nightlife really depressing... as if city goes on lockdown and most white people get out of the general area... cop cars everywhere. (granted, only spent 2 nights)
Baltimore: Ugh, having seen the best and worst of this city within a limited time frame, city just seems like a sham. Nice though.
Miami: downtown is boring. South beach doesn't pretend to be something its not: cheesy but authentically so. Fake but genuinely so. And the turquoise-water, white-sand beaches so close to the core... an amazing city. Would consider moving there.
Virginia Beach: someone needs to spread the word that this place is funky as hell... the whole tie dye t-shirt/ stoners on longboards element was completely lost on me. Interesting vibe.
EUROPE
Milan: more entirely modern than I had thought. Almost seems like a city settled in the 20th century. Not a very cozy city... very businesslike. Surprisingly imposing high-rises all around the core.
Rome: Like another poster mentioned, this city is just strange... trampled by tourists, the old architecture and sights definitely deliver, but all the locals seem depressed. Seems like a hard life there... disgusting graffiti everywhere (outside of the cliché tourist spots) almost makes it seem like locals are fed up with the city's posturing. Folks seem either unfriendly, or unconvincingly friendly. I feel like an overdose of tourism may have turned this city into a schizophrenic, coke-sniffing cynic. Definitely oozing in corruption as well.
Torino: expectations had been lowered after seeing Rome. City turned out being phenomenally clean, seems to be basking in wealth. Locals seem to love their city and embrace visitors. Oddly enough, this city seemed more 'international' than Rome... or in the very least more welcoming of outsiders. Also seemed much more functional than Rome - less corrupt. Come to think of it, seemed like a different country altogether.
London: See New York.
Paris: see New York, but the locals weren't as friendly/lively.
Geneva: impeccable city. Boring, only because I lack the funds. Definitely the most expensive city I've ever set foot in.
Lugano: Without a doubt, the most geographically blessed European city I visited.
Here's a photo I took in Lugano.