Mostly for financial reasons, I wish that videogames were more like movies and music, in that there were only one universal player. Then, people wouldn't have to make decisions about which system to buy, or which version of a game they should get, as every videogame out there would work in their player. This would also be beneficial to game companies too, as they wouldn't have to spend resources porting a game to two or three platforms, or research the demographic of each system, so they could focus on simply creating games. There could still be systems with special features as well, such as an expensive model that offered things like HD and online components, and a more basic model that just had the essentials. It would be similar to how some VCRs had special features like recording abilities, enhanced sound capabilities, slow/stop motion, etc.
Realistically I know this will never happen, for the exact reason stated: the three current major game companies are all striving toward different goals.