Google Maps I believe has constantly set the standard for online mapping sites. I stopped using all the rest simply because they could not keep up. Thought I would point out some cool new features.
When looking at streets in a city (works for Ottawa), once you zoom in enough, you will see the starting and ending house numbers for every block.
You will also see bus stops displayed on the map (again works for Ottawa). Clicking on an icon brings up route information and departure times.
Leave The Car Behind
Now when getting directions from Google Maps you can select your mode of transportation: car, walking and public transport. A few tests on the public transport option showed that it even had updated routes based on road closures. One thing missing would be a bike option. If your city has a lot of bike paths then this would be very useful. Currently if you select walking it does not seem to have information about walking or bike paths and instead sends you marching along the roads.