I have to agree with 17dman cause if you like weapons and like to kill a lot of people then get COD 4, but if you would like to go online then get COD 5 cause the online is great and nazi zombies is way fun. For me I like both a lot so there both good.
I would say Call Of Duty World at War, because it has way better graphics and the only reason CoD: 4 had better weapons was because it based in present day. so, of course the weapons are much better than WWII ones. W.A.W. also has Nazi Zombies which is something that makes this game simply awesome!
i suggest 5 is better. CoD 4 had amazing weapons and the maps are good, but 5 has amazing gameplay and somehow, the online is better than 4. It is much gorier, since you can blow people's legs off. and it is just a fun game overall
Yeah COD4-2 is going to be a great game but for now I would settle for COD5 cause the game is more realistic and it is so fun to play nazi zombies. BTW no you dont have to beat the game to play nazi zombies.