DirecTV HD question?

I am thinking of buying a new HD rear projection television. If I did this I would probably want to upgrade my DirecTV service to include HD programming which would require me to change my round dish to an oval dish with a triple LNB. However, I recently heard that DirecTV is planning to launch a couple of new satellites in the next year or so. Would this mean that the triple LNB oval dish would have to come down in a year or so and be replaced with some new bigger dish with the capability of receiving signals from four or five different satellites?