Game comparison, call of duty world at war, gears of war 2, or halo 3?

[?°?m€lody?°?]

Well, i like these types of games a lot, and i think cod world at war is an awsome game, but is it too difficult? and i think halo 3 is m,aybe one of the best halos, but is it true? and is it as good? and i never played any gears of war game, but my cousin said its a must buy...Do you think so?
so tell me, which game out of these 3 do you think is the best, based on graphics, online gameplay, story, and much more =]

 

[KW Mom]

Halo:best story and some good action .COD:World at War: best first person shooter action and best game play of the three .