This is the best place in the Southwest to go broke. Between Neimans, Barneys, Nordies, and all the boutiques, you will swipe that AmEx so many times, it will probably burst into flames.
But it'll be SO worth it.
If you don't have a rich&famous budget, don't worry. They have a great H&M, JCrew, LOFT, Ann Taylor, etc etc. And if you're a beauty addict - the Mac store is great (ask for Lauren), and the counters at the department stores are fabulous too!