My personal favorite maps always had numerous elevation changes whether they were city maps like "Turf" in Halo 2, The Pit and Valhalla in Halo3 or Sword Base in Reach. There were many others, but these stand out as prime examples. Multi level structures in a city environment similar to Headlong were able to handle a larger number of players and Turf was four on four and provided great slayer and objective play. Landscape maps such as Waterworks and Containment had so many points of attack and supported vehicle use as well as Containment's functional gates. Most maps I have mention were easily fought on foot but supported vehicles.
What kind of maps would you like and do you see the need for more maps that offer vehicles of some sort? What maps were your favorites from the past games and would like to see a similar style in Halo 4?
Edit: @ 7:45pm eEST
Having a map with 2 to 3 structures with stairs and lifts, streets to navigate with vehicles. High altitude mountain range maps with roads and foot paths that overlook the roads with man cannons that can launch you from on hill top to the other. Underground maps of sewer tunnels that are large enough for vehicles and have multiple smaller tunnels that occasionally drop into the larger ones from above or sides. Finally one that has heavy vegetation with winding paths and low hills and a high tree canopy allowing shafts of light through.
What would you like to see if you could create one?