Pokemon Blue

Ok here we go. This one will be easy. Pokemon Blue Version is exactly the same as the Red Version. There is one minor difference: In the red version you can catch ekans, growlithe, oddish, and mankey; while in the blue version you can catch sandshrew, vulpix, bellsprout, and meowth. So unless you prefer the game to contain one or more of the listed pokemon you will need the corresponding version. Otherwise getting both is pointless.

To learn more on this game I suggest reading my review on the red version at: http://www.epinions.com/content_192424939140