Actually It depends,
For the game that only have singleplayer mode
It is not nessacary to buy the Xbox 360 original one
Because you only play once
For example

Devil May Cry 4
Dead Rising
Silent Hill Home Coming
Prince Of Persia
Oblivion
Dark Sector,.....................
Lost Odysey


For the game that have nice Multiplayer mode,
you definately need to buy the original one,

Call Of Duty 4
Cod:World At War
Battlefield Bad company
Halo 3
Gears Of War,..................................
Racing and Sports Games

Thats why I have two console
If a game that only have nice single player only
I go for Xbox 360 version,for Call Of Duty and Multiplayer game,I go for PS3.Anyone agree with my opinion?