I agree with piano boy. If it is a nice day take a drive along the aux Highway 1A (between Banff and Lake Louise). Take exit to Johnson Canyon to access 1A. There are some beautiful picnic table stops along the way that over look the river. So beautiful.
Canmore might have better restaurants, but if the intent is to spend a day in Banff you will lose 2+ hours of it by the time you drive to Canmore and back, find a restaurant, eat... Seems like a bit of a hassle.
the driving time from Banff to Canmore is only about 12 mins, for me that is well worth lunch at Crazyweed. My opinion would be do do morning in Banff then head to Canmore for the afternoon (and lunch) or vise versa. The shops in Canmore are more interesting too!