Here are the things you should try to do on your first day (this may take more than a day if you are travelling with children)
Start out in Banff, park your car on or just off Banff Avenue and take a walk down Banff Avenue away from the river to the Park Information office and then back on the other side toward the Bow River.
On this side of the bridge is the Luxton Museum and a nice park. The post office is a block west, so you can mail your post cards.
Return to your car and head over the bridge. You can head right to the Trading Post, straight ahead for the Park Wardens Office (popular for wedding photos), or left toward the Banff Springs Hotel.
Park anywhere there's a free spot near the Banff Springs Hotel (valet parking and parkade parking are pricey, but if you don't have a choice...) check out the lobby, go up the stairs and find the back deck and outdoor pool with their stunning views. You can grab a bite in any of their fine restaurants.
On the way back, just after the Banff Springs, there's a right hand exit down to the Bow Falls, where the Bow River cascades over a rock ledge and are spectacular in Spring/Summer with the glacial melt thundering over. There's a little wooden walkway up beside the falls.
Return to Banff Springs Road toward town, make a left turn, and drive up the hill to the Upper Hot Springs Pool. If you have a chance, take a dip (great after a day of hiking or skiing!)
Head down the hill a bit, and watch for signs (on the left) to the Sulphur Mountain Gondola. This will give you a sky-high view of the region. If you are on a budget, alternatively hike up Tunnel Mountain, by the Banff Centre, for great views up and down the Bow Valley. Its a 20-30 minute hike, and not too challenging, even for young teens.
Head back to Banff Avenue, and turn left at the park (Luxton Museum) and first right to head toward the Trans-Canada Highway. Cross over the highway and head up the hill toward Mount Norquay. The roadway zigs and zags up the mountainside, and just before the ski hill is a great viewpoint. In the winter, skiers can ski from the ski hill right to the motel you passed on the left after crossing the highway! It's said from the top of the Mount Norquay ski hill, you can see the bottom of the ski run between your bindings!
Head down the road back to the highway, and this time turn right (west) toward Lake Louise.
Watch for signs leading to "Highway 1A", which is a nice two lane tourist route with spectacular views
When you see Castle Mountain, you know you are near Lake Louise. The town in the valley is nothing special, though its worth stopping in the Samson Mall to get info about the Icefields Parkway (this is a highly recommended Day Two trip, see below)
Head up the Lake Louise road, which climbs several hundred metres to the famous Lake Louise, and adjacent Chateau Lake Louise. Walk around the grounds, and maybe partway around the lake on the flat trail (the "Teahouse Trail" looks interesting, but it's a half day commitment, all on its own)
In summer, there is a riding stable and canoe rental on the south side of the lake, near the parking lot, and wonderful hike along the north shore of the lake to the glacier you see on the other end of the lake. Even more interesting, for those who have a half day (and good, fit legs!) is a hike to the right to the famous Tea House. In winter, you'll have to settle for a view of the ice-covered lake, and the cleared skating rink beside the Chateau. Head inside, as well, to check out this stunning example of castle architecture, not to mention there are several restaurants (and lounges) where you can eat & drink while enjoying the view.
When heading back to Banff, take the east exit (by Cascade Mountain and the railway tracks) for a side trip to Lake Minnewanka and Two Jack Lake
Head back to Banff and enjoy dinner at the many restaurants, and check out the many bars, pubs and nightclubs catering to visitors and locals.
Head east of Banff to to Canmore. The town, formerly an important coal mining town, is now the gateway to the Rockies and Kananaskis Country. The town has two great golf courses, Three Sisters in the valley and SilverTip, which has the second highest slope rating in the world!
When you get off the Trans-Canada head east up SilverTip Trail (to the golf course of the same name) to get stunning views of the valley to the west (morning light from this location makes for great photos!).
Head into town and up head to the Smith Dorrien Trail (gravel road) to Kananaskis Country. As you rise above Canmore, you pass the Canmore Nordic Centre, used for the 1988 Olympics for cross country and biathlon events (and it's used for mountain biking in summer)
A little further up the road you can get to Grassi Lakes, worth a short 15 minute hike for their stunning surrealistic colours.
Keep heading up the Smith Dorrien Trail until you pass the dam the Spray Lakes Dam, which are the Canmore water supply and you can drive along Spray Lakes for a few kilometres. The road is gravel (and dusty) so don't drive fast... you may also miss the You may have pass mountain goats and sheep on the slopes above or on the road! From the dam (on your way back) you have great views from above ot the town, all the mountains cradling the Bow Valley, and the Grassi Lakes.
Head back in to Canmore (stop at the Spray Lakes Dam for photos, and then walk Canmore's Main Street with its shops, restaurants, and Grizzly Paw Brewpub.
Here are suggestions for extra days in the Rockies:
Head west from Banff and about 7 miles west watch for the Sunshine Village turnoff. This ski resort straddles the Alberta - BC border, and has winter skiing and summer hiking (with a lodge right up on the ski hill!) There's a great gondola ride to take you up to the "Village". From the Sunshine Parking lot, there are several great hikes of varying difficulty, up the 22 km Healy Pass Trail
If it's September, one of the "Bucket list" hikes is the Larch Trail, starting out from Morraine Lake, 11 km south of Lake Louise's lake and chateau. You need a group of at four (bears!) and take a whole day. If it's a weekend, you may have to park in the "Overflow Parking Lot" on the Trans-Canada, and take the shuttle bus up, based on parking availability.
If you are less athletic or less adventourous, we recommend seeing Morraine Lake, and its rockpile, and drive back to Lake Louise (park in the large lot just south of the Chateau Lake Louise), and take a walk on the pathway around the lakeshore, for views of the glaciers on the currounding peaks, before rturnign to the Chateau Lake Louise and have tea or a meal in the Chateau or on the patio overlooking the lake (depending on time of hear). In peak summer season, and parking is limited/unavailable, you may have to park off the Trans-Canada in "Lake Louise Overflow Parking" and Parks Canada will have a free shuttle to Morrraine Lake and Lake Louise, and back.
Head past Lake Louise, to Castle Junction (under the shadow of Castle Mountain), formerly called Eisenhower Junction, and take Highway 93 south to Radium & Fairmont BC. The road has some spectacular views and moments, though it's about 2 hours to Radium. The eastern part of BC stays in Mountain Time like Alberta, so you won't have to switch your watches. Radium has a nice Hot Springs and two ski areas and number of golf resorts nearby. You can be back in Banff the same day.
Take the Icefields Parkway (Highway 93) north to Jasper. Worth a detour: Bow Lake & Glacier, Peyto Lake. Continue north to the Columbia Icefields, and the Athabasca Falls. new attraction is the Glacier Skywalk, near the Columbia Icefields (run by Brewster).
In Jasper, three things are truly worthwhile: the Jasper Tram (just south of town), The Jasper Park Lodge, with its bicycling room service waiters, just north of town and across the Athabasca River, and the Miete Canyon just north of the town. If it's late and a night-time drive back to Banff on the twisting mountain roadway seems daunting (and you'll miss out on the views), you may want to stay the night and drive back to Banff in the morning. Be sure to fill up in Jasper, before returning, as there is no gas station btween Jasper and Lake Louise.