I've only played Halo Reach a few times at a friends, but from what I have seen I am more of a fan of Halo 3. Halo 3 set the bar so high, that it is almost impossible to beat it. This kind of reminds me of the situation with COD4 and COD5. If COD4 wasn't so highly acclaimed and popular, World At War probably would of received extremely high praise. It's always hard for video game publishers to satisfy their customers nowadays, especially when they have so much hype to live up to in this circumstance. In the end, I think Halo 3 comes out as my ultimate decision. There's not much that can beat it.