I went to Ottawa on a business trip a few years ago in late January/early February (I forget). I was able to check out the Parliament Buildings and the such. However, it seems like nearly every leaves the downtown core after work so it's kind of dead in the evenings. I wanted to skate the Rideau Canal but unfortunately it wasn't frozen over enought at the time. It looks to be frozen nicely this year.

I haven't been to QC but have heard very nice things about it also.