Good man! You got started on this early, unlike your Christmas present shopping from this past Christmas
Waterton is solid, can't go wrong with Jasper either but make sure you call ahead for hotel booking.
I know Banff is a little predictable but my g/f and I stayed at a really nice lodge just outside Banff and had dinner at an Italian diner in Canmore.
Maybe a rip down the Cowboy hiway to Turner Valley or Black Diamond? Couple of really nice diners in both town. I forget the name but the main hotel/bar in Black Diamond was recently on "You gotta eat here". And the drive down the cowboy hiway is incredible just before sunset. Maybe bring a blanket, lots of nice farmers fields