What parts of Canada are you most interested in? Large cities and major highways in well-populated areas like southern Ontario or BC's lower mainland? Or are you more interested in the boonies?
For areas of the country with high population density, any maps that use Navteq data are pretty good coverage in Canada. That would be Microsoft
Streets&Trips and Garmin's City Navigator North America. Both use the Navteq data for their maps. You can use the Garmin maps with any of their personal navigation devices or with their Mobile PC or nroute programs on a laptop.
Microsoft Streets&Trips can be purchased with or without a very good GPS receiver (the Pharos 500). I think you can catch some excellent sales on the 2008 version these days .... probably get the whole software/hardware package for the price of a good GPS receiver.
You can get
Garmin's Mobile PC complete with City Navigator North America 2009 (one year newer map data than Streets&Trips 2008) and a Garmin GPS-20x GPS receiver for about $99.
Streets&Trips 2008 is great for trip planning and not so great for navigation.
Mobile PC is a stellar personal navigation application but is not so hot for the trip planning stuff.
If you need good coverage in the boonies in Canada about the only product I know of that fills the bill is Garmin's
Metroguide Canada. The data is from DMTI Spatial in Canada and is excellent. Unfortunately it's getting pretty out of date. It's still for sale but Garmin has abandoned it and won't be doing any future releases. That's not an issue for main or secondary highways and grid roads or towns and villages that have not seen a lot of growth, but in areas where there has been a lot of development it can be an issue. I don't know of any other product with such good Canadian coverage outside the high population regions.
I'm not familiar with iNav and some of the other products that are featured on here so perhaps someone else can comment on their Canadian coverage.
...ken...