If you have to do one "good" hike in the Banff area I would suggest this one. It will take you the better part of a day.
There are two hikes, one to the Corey Pass (5.8km one way, 915m climb) and one to Edit Pass (4.6km one way, 460m climb) but you can join the two by a path cutting around behind the mountain. We found the Edith Pass to be boring because you are surrounded by trees at the top. However, as you continue down toward the Corey pass you see a beautiful valley and the scree field on the back of the mountain.
Here is the view, towards Banff, part-way up the Corey pass.
Looking up towards the pass you will see mountains and Big Horn sheep:
After going over Corey Pass you will go down a long scree slope that gradually grows larger and gives you an excellent view of several valleys.
Part way down the scree slope you will see this when you look up at the pass
Here are some other views as you go down from the pass and behind the mountain.
Once you have gone behind the mountain you will climb towards Edit pass. This trail goes thru the forest. Here is what you see where you just come out of the forest.