It depends how long you have to travel and what type of environment speaks to you. The east coast of Canada has some of the friendliest communities you'll ever visit, delicious food, and great hiking in Nova Scotia and Newfoundland & Labrador. The west coast has iconic mountainous regions with great hiking, snowboarding, and mountainbiking; and with Vancouver, you have a great city centre to explore. In terms of "central" Canada, Ontario-Quebec has a great mix of everything and areas that I'm most familiar with.