Natural Resources Canada has created a digital topographic map for the entire country that can be viewed in Google Earth. The map is based on the WMS map service, which can be a little tricky to set up in Google Earth so I went ahead and set them all up. Just click on the link beneath the screenshot to access the maps.
The main map layer (Toporama) contains all 16 of the data layers. Most people will only need to use this layer. The farther you zoom in, the more detailed the map will become. The highest detail is based on the 1:30,000 CanVec database.
I have also included each layer individually in case you just want to pick and choose which data to view. Note that each layer has different view extents, so data may not be visible if you are not at the correct zoom level.