With any big corporation, especially in video games, there's always a mascot and/or memorable titles to give said corporation an identity. It's obvious that Nintendo has Mario, Zelda, Metroid, Kirby, Animal Crossing, Pikmin, etc. (and technically Pokemon as well). Sega has more than just Sonic, such as Yakuza, NiGHTS, Jet Set Radio, Puyo Puyo, Crazy Taxi, etc. Even Microsoft has Master Chief and many more (including Flight Simulator).
So the real question is this, does Sony ever have a corporate identity in the video game industry? The only identity that I can find for Sony is their movie/TV output such as Spider-Man, Ghostbusters, Men in Black, Charlie's Angels, Karate Kid, Seinfeld, among others.