For consumers in any industry, competition can be a wonderful thing.
Not only does it increase the quantity and choice of options available, but it ensures companies are kept on their toes, pushing themselves to produce innovative and high quality products. This is just as true in the world of video games, where rivalries and competition amongst consoles, companies, games, characters and gimmicks have helped push the boundaries on what is possible.
The gaming industry can be more passionately opinion-based than most of its entertainment contemporaries, so proclaiming a 'winner' for the biggest showdowns can be difficult. Outright sales doesn't always indicate a better or more influential game, and even the very worst received titles will have their staunchest defenders leap in when any competitors show up.
Nevertheless, there are certain rivalries out there that most gamers will unite behind, and agree that the case of a competition between the two has been fairly rounded out, be it through units shipped, influence or overall reception.
Many of the most historic rivalries have some pretty definitive winners, if we're totally honest.