Ralph, I've noticed that several studios have installed Pergo (qv) floors. It's a type of laminate which is relatively inexpensive and holds up fairly well under the stress of dancing.

A hardwood floor is ideal but it must be installed correctly for dancing and, even worse, it must be maintained. Accordlingly, hardwood floors are very expensive.

If your house is built on a slab then you must use engineered hardwood instead of solid.

jj