The best tree runs are at revelstoke (that i have been to). top to bottom trees. Lots of good terrain in the banff area, sunshine village, lake louise, kicking horse, and 2 other resorts if they get dumped on. Castle and fernie are good to but they are a bit more isolated from the rest. They are south.
Some other guys who have more experience will let you know more options (ie, white water and red mountain).
I have only ridden one hill in the vancouver area and it was when i was first starting so i can't really compare interior bc/alberta to the whistler area.