HC: I agree about taking your own skis.
Without commenting on the totally overblown, mega-hyped, completely overdone, and hopelessly lame trend toward fatter and fatter skis (
), I'll just add that the chances are better than even that your current skis will be just right for the conditions.
If you do get lucky and have storms roll through, two suggestions for renting would be the K2 Phat Luv (an awesome women's powder ski) and the Head Sweet Fat Thang.
A *slightly* longer ski that what you're on right now will float a little better and help you maintain your momemtum. Also, fore-and-aft balancing is a bit tricky for people who don't ski powder all that much - a longer ski will help a little with that as well.
Have a great time.
Why don't you talk NBS into coming to Jackson Hole sometime?