halo is better than most of the other fps games like gow2 and cod5.
not because of the story or multiplayer but because custom gametypes and forge makes the possbility's endless for people that have some creativity.
there are more war games of actual wars than sci-fi without mindless carnage(super alien zombies of doom) all the time.
halo 3 odst's campaign does look good since you get some new tactical weapons and you have to keep in mind that you have health and not recharging shields. firefight is gonna be fun since the enemy's are looking for you and not vice-versa.
and also, i always wondered what happend to new mombassa after halo 2.
id play this over a ww2 game anyday.