Like the title says, favourites from halo 4. Weapons, maps etc. Ill give mine first.
Map - Adrift/Haven
Loadout Weapon - DMR/BR & Plasma Pistol/Boltshot
Ordinance Weapon - Scattershot/Incineration cannon/Damage boost.
Armour Ability - Promethean Vision/Thruster Pack
Upgrades - Dexterity/Mobility/Ammo/Sheilding
Gametype - Team Regicide/CTF.
Campaign Mission - Reclaimer (just because of the cutscene with the Librarian, adds so much to the story) and Midnight (cause its the final mission, also jet flying).
Soundtrack Song - 117/Revival
Add more favourites if you wish, thats just all I could think of right now.