I've travelled across most of this country, and have had some pleasant, as well as not so pleasant surprises.
From West to East:
Victoria - I was surprised that there was no beach within city limits.
Spokane Washington - the string of skywalks connecting buildings in the downtown core.
Medicine Hat - a veritable oasis in the heart of one of the driest parts of the southern Prairies. The river valley made for a scenic backdrop. I'm not sure I was expecting much of anything as we approached Medicine Hat - but I remember being pleasantly surprised.
Moose Jaw - at one time Moose Jaw was just as big as Regina or Saskatoon. I wasn't expecting to see larger historical buildings in the core of a town this size (i.e. especially compared to Grande Prairie)
Winnipeg - Incredibly Flat. In fact, Saskatchewan is almost mountainous compared to how flat I found it around Winnipeg. The only place I can compare this to is parts of the Netherlands. (p.s. Flat refers just to the geography, not the people!

)
Chicago - I had expected this to be somewhat of a gritty city, with a typical urban mix of 70's style Sears Tower (sorry Willis Tower) like highrises interspersed with parking lots and rundown smaller buildings. What I did NOT expect was the level of historical highrises, art deco detailing on buildings and walkability of the core. I could have easily spent a few more days in this city.
Hamilton - the number of historical buildings in Hamilton astounded me, especially since most Torontonians led me to believe it was an industrial armpit. Hess Village had a nice vibe with all the sidewalks pubs.
Guelph - I wasn't expecting so many older buildings in the core. Also, a lot of Ontario towns have redbrick, so Guelph's abundance of historical fieldstone buildings gave it a unique charm. The old fieldstone church overlooking the downtown not only provided great views, but also made a great photo opportunity in and of itself.
Niagara Falls - I wasn't expecting the level of kitsch, especially more pronounced on the Canadian side - but Clifton Hill was a riot, once we got ourselves in the right mood. I take visitors here all the time now.
Montreal - I had only ever seen pictures of downtown Montreal, so I thought their oldtown consisted of the older buildings on Ste. Catherines and Sherbrooke. Imagine our surprise on our second trip when we discovered the "real" old town

)
------
I've never been to Quebec City, as I'd tended to hear negative things about it... but based on some of the positive comments from certain posters - I'm thinking this city might become my next urban destination to explore in Canada.