For many, many years Scottsdale Fashion Square has been a great place to see and be seen. It's hard to not find what you are looking for. Personally, I love their Dillard's and the Nordy's is better than any of our cheesy little So Cal Nordy's. (Nothing compares to Seattle/Bellevue and Miami for Nordy's, though.)
This mall continues to grow, recently upgrading a few of the restaurants and bringing a really large Barney's to the Southwest. I'd take this mall any day over South Coast Plaza, the Grove and/or Fashion Island in LA. It seems more relaxed and the pace is less hectic.
If you decide you must brave the mall at Christmas, be patient with the parking. Folks seem to have a tough time parking their rigs in the well-lit huge garages surrounding Fashion Square. Parking is free and there's no 2 hour time limit imposed on you.