Hi, I was in Ottawa two summers ago, never in the winter. The Rideau canal is very nice, with locks on one end empting into the river and supposedly the canal becomes an ice skating rink this time of year. Also, the parliment building is nice and there is a park across the canal, in front of the national gallery museum, which is also really nice. There is a bridge next to the national gallery museum that goes to Gatineau, you can walk across, civilization museum on that side and views of Ottawa skyline. Lastly the Byward Market is nice, well at least in the summer it was, they said that it gets really cold there in the winter, so good luck.
<a href='http://www.rangefinderforum.com/photopost/showgallery.php?cat=500&ppuser=1193'>My Gallery</a>