Tell me?
The ark is really awesome because its so open and the battle never get old-very re playable
From each game:
Halo CE - The Silent Cartographer
Halo 2 - Quarantine Zone
Halo 3 - The Covenant
Halo 3 ODST - Any Mombassa Streets segment
Halo Reach - New Alexandria
Halo 4 - Infinity
Halo 5 - Swords of Sanghelios
I cant pick one there are soooo many that i absolutely LOVE.
I really like The Silent Cartographer and New Alexandria. Bungie really knew how to set the right tone for their missions.
Outskirts from Halo 2 is my utmost favorite because I loved the design and I had fun getting out of the map and finishing the level without being inside of the map (kill all enemy AI from outside the map, then get back inside the map and walk to the finish lol).
The covenant
The final missions of Reach. The Package, The Pillar of Autumn, & Lone Wolf.