mac, I was there in mid September and can promise you it was the most photogenic trip I have ever taken. For sure, if you can, stay at the Fairmont like bspraque suggested. Lake Louise is a Canadian treasure and staying there will give you best access to it. Several others have suggested Darwin Wiggett's books. Listen to them. Wiggett is a wealth of info of the best kind. The name, Icefields Parkway , may not sound photogenic, but it was designed with tourists/photographers in mind. There are huge road shoulders all the way up so you can pull-over anytime to shoot scenics or wildlife and there are plenty of both.
The Dman mentioned Moraine Lake in the Valley of the Ten Peaks. Get there early, others will. When I was there we had an overnight snowfall and the area was magical. Teton viewer mentioned a waterfall north on the Parkway. Athabasca Falls is fun. You can safely climb all over the area for great shots.
Make sure you visit Yoho National Park between Banff and Jasper. Emerald Lake is not to be missed. And the Lodge there is a great place to stop for lunch.
Have a great trip. Share shots when you return.

Hi,
I am native to Alberta and I am shooting in the Canadian Rockies for years. This place is so spectacular that for the firs time it is not really important were you are in the Parks. Also time you selected is not the best. You will definitely will need warm closes. and weather could be quite nasty with rain, winds, and quite possible snow in higher altitudes. I believe July and first part of August is better. The temperature warmer, days are long and you will get a lot of time with the "blue hours". In October your daylight much shorter. I did number of shooting in October last year and had to look up suitable weather and lighting. Few years back I was there with my friend from US in early August and we were snowed on at the Columbia Ice Fields.
Good luck
Assir.