From a console technolgy standpoint, it would be Sony. (Cell, Blu-ray, complete media hub, handheld to console interaction)
From a online technology standpoint, it would be MS (so far). (XBL)
From a population reach standpoint, it would be Nintendo. (sold more to old people, kids, etc.) I can't say the balance board because it was out before as a Jackie Chan product. The motion controls have been done before and the PS3 came to market with it first.