Valhalla, Sand Trap, Guardian, and Even Rat's Nest. Valhalla is great because of the layout and spawn points. And the fact that equipment and weapons spawned at the base, where you can grab it right away, potentially helping you take down a Wraith or Banshee waiting nearby. Unlike in various maps in Reach, where you have nothing to counter those vehicles circling the spawn points, leading you a near instant death.
And at least you had the ability to spawn on the other base, away from vehicles.
Anyway, Sandtrap is one of my favorite maps. It was a huge map, not complicated, Spartan Lasers and trip mines on each side, allowing for great anti-vehicular support. Maps like that would be great.