Matthew Gallant, of the site gangles, has typed up the history of the famous A and B buttons! Taking a look at Nintendo, Sega, Microsoft and Sony.

It starts from the revolution that was the NES controller with the break away from the joystick fad to the DS where the article's author was shocked to find it A and B instead of B and A. Though the basic functions have been kept the same, designs have changed. Sega and Microsoft consoles have been similar, also using the A and B theme. Yes Sony is in there too, they may look different but X and O do the exact same stuff when you think about it!

A is your positive, B is your negative... or something like that. Anyway, the article describes the design of each console and the evolutions over time.

So remember kids, it used to be B before A in the alphabet of video games.