yes even tho call of duty may look more realistic (it's games were always on the top of the best graphics and detail list) but compare the change in graphics from halo 2 to halo 3. big diff.
I would have to go with call of duty 4.halo 3 is fun but it gets old after a while on online. while call of duty 4 was smart and made it so you have to get to a certain rank to get a certain gun, so you're motivated more to keep playing