I <3 Halo:Reach - amazingly fun and best campaign + amazing Soundtrack
I <3 Halo 3:ODST - best soundtrack + Firefight + Coastal Highway and Mombassa Streets, amazingly unique campaign.
I <3 Halo 3 - best multiplayer levels + Forge + best Custom Games + soundtrack
I <3 Halo 2 - amazing huge fun campaign + soundtrack + Fun multiplayer
I <3 Halo: CE - started it all
Because you need to hit dead on with it. It really is hard to use. They bounce of the ground 90% of the time, and have a very low blast radius. Thus why each clip hold 6 or so shots, and the rocket launcher only holds 2.