Locals always have there favorites and you never know what kind of biased opinions they may have about their favorite skiing destinations. Banff is no different. There are three main hills that Banff-ites or patrons have the option of visiting, Sunshine Village, Lake Louise and Norquay. Each hill holds great benefits and disadvantages. I may have my favorite but I will share my thoughts on what each hill has to offer and let you decide for your self.
Closest to Banff is Norquay. It is literarily cross the highway. This is considered the locals family hill. A small facility with six chair lifts, 60 runs, 190 acres and a vertical drop of 503 meters (1,650 feet). The thing people love about this hill is how kid friendly it is. with the bunny hill right next to the lodge and a drop off zone just meters away it makes it easy to haul your families gear to where it needs to be. It also have a reputation for being very steep and fast. There are some shorter and less steep runs easily accessible but you can also get some serious challenge off of nuns like the Lone pine off of the North American chair. Norquay Also hosts night skiing. This can be a fun way to spend a week end night with the family. There is a nice sized terrain park and a dedicated maintenance crew. the down side to this is there does tend to be a good number of young adults consuming recreational drugs and foul language open for everyone to experience. And if you want to try something different the tube ride can be just as much fun.
Further West the first facility off the highway after Norquay is Sunshine Village. Shine boasts 12 lifts, There is a well maintained paved road off of Highway 1 that leads to the parking lot. All told the parking lot/base of Sunshine is ~ 15 min from Banff. From the parking lot access to the base of Sunshine is another 15 minute gondola ride. Ultimately you get off the highway sooner that you would driving to Lake Louise but it takes just as long to get to the base. Generally you are saving in gas and its seemingly safer because you spend less time on the highway. However, there can be some serious logistical issues.
Because of the National Parks policies in expansion Sunshine regularly runs out of parking space and has to direct people to park on the road leading up to the hill from her you have to catch one of their busses to get to the gondola. This can add an extra half hour to your approach to the base. Enough about the parking, the skiing at Sunshine easily rivals Lake Louise. There is ample terrain from steep, high consequential alpine runs to technical tree and pillow runs. Slack country is easily accessible. Most notable of the steeps is the famous Delirium Dive. This gem has arguably the best terrain that is regularly controlled for avalanche. Its aspect protects it from both the wind and the sun and it is massive.
Rivaling Sunshine Village is Lake Louise. This facility has 16 4 runs, 1700 hectares and 11 lifts (1 gondola, 7 chairs and 3 carpets). Lake Louise is a monster with multiple options for extreme terrain. In many ways Sunshine Village cannot compete due to the difference in aspects and steepness. Lake Louise in general is steeper and holds a larger area of wind loading aspect. There is a lot of easily accessed terrain that is classified as extreme. The entire ER ridge (Eagle Ridge) collects snow from wind and there are many pockets of secret areas if you can identify them. Also the new West Bowl hold many cliffs and drops that are now inbounds and regularly controlled. The traverse out of West Bowl can be a pain. Lake Louise will see more snow from a Chinook weather system and typically holds its snow pack well.
Overall if your visiting Banff, Canmore and the Bow Valley these are your three best options. There are other facilities further away that are also notable. Kicking Horse Resort in Golden BC (worlds best champagne snow), Fernie Alpine resort (massive snow falls), Castle Mountain Ab (the upslope secret) and Nakiska closest to Calgary. I have not included these resorts as they are not what I would consider "Bow Valley" or without logistical add-ons for visitors to Banff/Canmore.
If I had to chose between one facility for a single day of skiing I would consider these things.
Lack of snow with high pressure and cold temps: Lake Louise I believe will deliver the best conditions in the wind loaded areas (even during high pressure systems there seems to be wind at alpine levels). Lake Louise holds is snow quite well and the steeper aspects tends to avoid moguls.
Transitional weather systems (cold to warm and visa versa) out of the west: Sunshine typically will have the best snowfalls during these times and with its sheltered aspects will see the most stable snow packs in it extreme terrain.
Chinook systems (overwhelming and uniform weather flows from the west resulting very warm winds exiting the mountains): look to Lake Louise for snow and not rain.
Up slopping weather systems out of the east: Norquay is further east than both Lake Louise and Sunshine and will likely get more snow at these times. Consider Nakiska or Castle Mountain with upsloping systems (typically early and late winter/Fall and Spring). Keep your eye out for this phenomenon
Family fun: Norquay for the beginners and wallet friendly experience. Novice and beginner groups are best to start here for lessons and move on after a day or two. Sunshine holds many low angle and easy runs for kids and novice skiers/riders. Norquay has night skiing and a tube park, this is a fun way to spend an evening with everyone. LL is overall steeper and can be more challenging in general go here last.
For the park rats: a lot of things have changed since I spent my days in the park. From my estimation both LL and Sunshine have excellent terrain parks. However I think Sunshine has more diversity and intermediate level features. Again, Norquay has night skiing and has park features in the night skiing area.
Extreme terrain: Lake Louise is generally steeper and has it West Bowl that is full of drops and cliffs that are in bounds. There are so many opportunities for steeps throughout the entire mountain. Access the Dimond Mines, ER ridgeline, and West Bowl right from the chair lift. Hikers paradise will get you areas like Brown Shirt and
White Horn Chutes (these are short runs for the length of hiking). Sunshine Village's Delirium Dive requires a small amount of hiking but offers a massive area of extended extreme terrain with long runs. Hike a bit more into "The Dive" on the Galaxy Ridge to access the Galaxy Chutes for even more. Sunshine also boasts the Wild West. This area holds shorter runs than Delirium Dive, however there are some small cliffs and slot canyons that are so much fun. Both Delirium Dive and the Wild West require avalanche equipment to access them. Sunshine Villages way of try to keep unqualified guests out of these demanding areas.