Regency TR-1 (1954)

 The Regency took radio out of the parlor and put it in your pocket. Jointly produced by Texas Instruments and TV accessory manufacturer IDEA, the TR-1 was the first consumer device to employ transistors. The $50 item didn't sell well--Sony did much better with a similar product a couple of years later--but it inspired a host of imitators, which in turn helped popularize a then-obscure genre of music known as rock and roll. If not for transistor radio, nobody would have been dancin' in the streets.