6. Sword Base (Halo Reach)
It's true that Reach had some of the worst maps in the series but it also contained the excellent Sword Base. The level design was beautifully balanced, no matter what your play style meaning this was the go to map for custom games. The multi-tiered bridges connected by a myriad of twisting staircases added tremendous scope and variety. The added gravity lift on the bottom floor meant aerial combat was fast and furious, while the buildings provided ferocious close quarters fighting. While not as impressive as some of the higher ranked 'small' maps, Sword Base was perfect with the new abilities incorporated into Reach. The camping room at the top of the base meant survivors were hilariously overpowered when playing Zombies but other than that, it was the best Reach had to offer.
Best Game Modes: Territories, Free For All and King of the Hill