Canada is so vast, that the easiest way to get around the country is to fly, and Air Canada provide excellent connections between the main cities that allow you to do this. Individual areas, such as British Colombia, or The Rocky Mountains are best explored by car, and most major car rental companies have offices either in the cities, or at the airports.
Another option, and one that is particularly popular during the summer, is to rent a campervan, and take off into the wilderness for a few weeks camping holiday.
The Rocky Mountaineer Train runs from Vancouver to Jasper and Banff, and is considered one of the most spectacular railway journeys in the world.
There are many cruise companies that operate services along both coasts of Canada, allowing you to see the ice floes of the extreme arctic north as well as the spectacular costal scenery along the way.