Halo 3 all the way.
Gameplay, STORY, and great but awesome extras.
Gears could hve better graphics and allf oof that. But Halo gots also tremendous graphics, do you know why? Well beacuse first its images are very clear and lighted with colors, Gears of War normally is dark and it falls in clearness. The other well Halo is a perfection when you play online, NO GLITCHES!!!!! In Gears of War you got more than 10 glitches and more than 10 graphic erros. Thats all I can say about these 2 great games. Is not that me a fan says so, because it is the truth.

P.S: A detail I like in Gears very much is its Blood effect :P, c ya.