I would pick Saltspring Island off of Vancouver island. It's big enough that it has decent shopping. Great summer climate and just a little less damp then Vancouver. If you miss the snow, head to Whistler. You are a short ferry ride away from awesome saltwater fishing and freshwater fishing. There is even decent fishing on the island. Just a very beautiful corner of this world.
Out east looks nice too. Perhaps some place central so you would be close enough to PEI, Newfoundland, Cape Breton and Southern Nova Scotia shore. What I have seen of Northern Quebec is also great.
If it had to be Ontario, then I would want to be above the hummid/smog belt which can extend to Sudbury/Northbay. The Nipigon area is awesome, Tamagami, and LOTW.