Mine would be Narrows from H3:)
DESPITE WHAT EVERYONE SAYS, I’d say Narrows is the worst map in all of Halo. It’s so one-dimensional. It’s nothing but bumrush up the middle or constantly get flanked from the mancannon.
My favorite would have to be Sandtrap. Ghost Town is really close though.
My favorite map is blackout which kind of is still being used today but made using forge maps but mostly that one snow map with the bases built into the mountain, it had a cave in the middle and man cannons in the cave that shoot you across the giant hole and they where also outside of the bases, they shoot you up to the top, it was in halo 3 and I think it was the heroic map pack or something.
Boarding Action. I miss those epic Sniper-screen-peeking-duels so much.
Guardian, Last Resort, Narrows, Orbital, and The Pit. Ivory Tower too.
Whenever I think of Halo, these are the maps that come to mind. It’s funny how I’ve played the most recent Halo games much more than the older ones, yet I think more about the older maps.
Favourite Halo 4 Maps:
Longbow, Solace and Haven. Detest Abandon and Ragnarok is mediocre as it favours too much DMR action.
This belongs in General Discussion or Halo Universe, but I’ll respond anyways.
I am a big Zanzibar/Last Resort fan, my Speedrunner name is actually mr ZanZibar. 
I also like The Pit, Guardian, Waterworks, and Midship/Heretic. My Favorite all-around would have to be the Blood Gulch Legacy: Blood Gulch, Coagulation, Valhalla, Hemorrhage, and Ragnorak. Sidewinder/Avalanche are pretty fun as well. But nothing beats Team Duals on Snowbound/Boundless.
Battle Creek. Loved games of Shotty’s on that map, that was just crazy fun.
Rat Race.
Headlong.
Started in Halo Reach, so I’m gonna say Sword Base, best map in a Halo game.
…
Joking, that’s psychological warfare on the worst level.
I’m gonna say Uncaged. Not a lot of camping spots, and I like the floating stadium environment.
Terminal. It was something that was completely new to shooters. Also, it was hilarious. Generally a good mix of everything.
> Boarding Action. I miss those epic Sniper-<mark>screen-peeking</mark>-duels so much.
Burn him…
Burn the screen looker.
Just kidding, that was part of the fun with LANs. Caught screen peeking? Expect a fist in the arm shortly >;)
My all time fav. map? That would have to go to Lockout. So many fond moments going on sword dominating sprees on my closest friends >:D
lockout and headlong
Midship. by far my favorite.
> My favorite map is blackout which kind of is still being used today but made using forge maps but mostly that one snow map with the bases built into the mountain, it had a cave in the middle and man cannons in the cave that shoot you across the giant hole and they where also outside of the bases, they shoot you up to the top, it was in halo 3 and I think it was the heroic map pack or something.
Avalanche. I loved that map, they really improved upon Sidewinder.
Avalanche and Last Resort.
My favorite new map is probably Solace, it’s just too bad it’s generally hated for not being a DMR snipe fest and thus never comes up in matchmaking.
Standoff from halo 3
Containment, best BTB map ever. Tons of cover, tunnels, HUGE bases, lots of vehicles, teleporters, switches and gates.
Epic map, my favorite in any Halo game.
Waterworks is a close second, huge BTB map, falling stalagmites, banshees, ladders, tons of hiding places.
Halo 2 had some of the best BTB maps period.
ASCENSION!!! I have a lot of memories on that map. I pretty much love most of the Halo 2 maps.
Lockout, Midship, Chillout, Guardian, Damnation, Blood Gulch, and Beaver/Battle Creek