Mimi, thanks for the tip on the Nike Frees. I've been looking at those for awhile and wasn't sure they were worth the money. Maybe I'll get a pair for walking and knocking about in.
I recently bought a pair of Newton Running shoes for running, and so far, so good. They are designed to "encourage" you to strike mid-foot instead of heel, and they feel good. They are made out a mesh material that doesn't cramp in your feet, like traditional running shoes. Kinda pricey but if they keep my piriformis syndrome and ankle woes at bay, they are worth it.