I don't think Sony will ever be on "top" again. Japan in generally just isn't the player they used to be, they can't compete with Chinese/Korean companies that can undercut them on labor costs.
Japan's dominance of the electronics sector was largely due to the fact that China was so far behind technologically in the 1950s-80s and kept consumer manufacturing to controlled levels before letting it explode in the 1990s.
You look at Sony, Sharp, Panasonic, etc. today, they're all in big trouble. Of the three though I think Sony is the best bet to bounce back to some form of positivity though, but I would research their stock quite a bit. It may be more beneficial to buy bonds from them rather than their stock.