Not having done much "on street" bike commuting while I was there, I'm not going to try and verify Ottawa's growing reputation as a bike-commuting paradise. However, walking around on foot (in the U. of O. area) it was obvious that cycling is a huge mode of transportation in this city.
What I can gush about were the scenic rides I was able to get in... on the Rideau Canal, and along the Ottawa River. The canal ride seemed to be more or less through the city-proper, and riding around 7:00am there were tons of other cyclists and joggers out using this multi-use trail. And the Ottawa River ride, on a warm late spring afternoon, was just gorgeous. And the trail went on forever... winding scenically along a beautiful and historic waterway... and when you come into town, you're right behind the Supreme Court and the Houses of Parliament and have snuck your way straight into downtown Ottawa.
Dow's Lake, early morning:
The Ottawa River... somewhere in the Nepean area
And this, just for the heck of it, is the University of Ottawa pedestrian / cycling bridge across the canal: