Spire… Or Breakpoint, if it would be a 8v8 Map
Tempest, if 6v6
Every Anniversary Map Pack Map for 4v4 (The Small Ones of Course)
…but my overall Vote goes for “Spire”.
Edit.: Ouh, I totally forgot the “why” Part:
Spire -> One of my Favorite Maps of all Time. Especially, since it was an Invasion Map, too. I loved the Dirty & Dust Setting of this Map It got plenty of Cover & the Spire would make an Option for insane Ground Pound Moments. If u think further & would “mirror” the bottom Part of the Map/Extend the Map behind the Spire it could be an awesome Warzone Map.
Breakpoint -> Similar to Spire, it was an Invasion Map too (I played mostly Invasion in Reach). I can’t say much, but I loved the Fights on this Map. U could try to get the Snipe, climb the Mountain and had an Overview of the whole Map, except the Tunnel. U could have fights in the Mountain, u could have fights in the Tunnel and especially Objective Gametypes worked well for that Map with a lot of Options to go, after u grab the Flag.
Tempest -> Especially the Theme & Layout of this Map was good. U had Tunnels “behind” every Base were u could went on Foot & then u got the Middle, which u could control with a Warthog & that was another good Part of the Map, Vehicles weren’t totally useless. Paired with the Power Weapons this was a really good Map.
Anniversary Maps (4v4): Since they are not originally Reach Maps I try to stay short on this Ones → What I loved most was the Nostalgic Feel and the Setting/Atmosphere of this Maps. They were just soo beautiful. I could stare at them for Hours. Even if they got Extra Paths, they still had this Nostalgic Feel & worked just so well with them. I would even Consider them better Maps, than the Original Ones. I mean, somehow DLC Maps get more Love from the Devs, especially from the Aesthetic Side. Just look at High Noon, Battle Creek, Solitary, etc. They were all Different. Not the Same Aesthetics, not the Same Buildings and Blocks, etc. I would even call it the Best Halo Map Pack of All Time, so u can Kind of Understand, that I would give every Map in there my Vote, without going any further… ^^