A lot will depend on what type of shops you like to do. I've shopped most of these areas so my opinion:
Orlando - Lots of shops. LOTS OF TRAFFIC. Great weather if you're going in the winter.
Memphis - Not the safest city in the world. The joke in the mid south is they check you for guns when you enter the city and if you don't have one they issue you one. Not a ton of shops either. Although if you time it right you could get some good bonuses.
Austin - Decent amount of shops, perhaps my favorite city in the US. Would probably be my choice from this list
Las Vegas - If you have an NV work card maybe, if you don't, no.
Portland - I've only been here once but some decent shopping. Personally wouldn't go in the winter
Minneapolis - The only place on the list I've never been
Tucson - Interesting area but doesn't seem to be as many shops as other areas.
New Orleans - Shopping wasteland. Actual wasteland outside of the Quarter.
There are reasons that a body stays in motion
At the moment only demons come to mind