We've been visiting and photographing Peyto Lake for years (even watched one of the best auroras here) and it's one of those spots that truly never gets old.
While it is a touristy spot, it's an absolute must see along the Icefields Parkway. There is a short trail leading to the main viewing platform, but if you want to get a more peaceful experience, there is another less visited viewpoint with a big rock located around 500 meters further southwest from the main one.