With the improved singal/noise ratio p0lar described, CAT6 can carry 10GbE speeds for up to 55 meters.
CAT6A will go the full 100 meters with 10GbE. Once again, the termination, testing and certification requirements to fully appreciate this performance are not cheap.
I personally recommend installing the best wire available when the walls are open, using the industry standards for routing, bend radius, support. It is a bear to come back and drag in better copper later.