How about this idea for part(s) of the map:
A deserted highway, full of bombed out cars fleeing the city, like a few scenes in the film I Am Legend. Maybe it would resemble the
Highway of Death. Maybe it would foster a motorcycle gang or highway-based civ. Also, you might want to give serious though to how roads and highways would factor into a post-apocalyptic world, given the massively reduced capacity to build roads worldwide. Perhaps make road-building an Era 2 or late Era 1 ability?
Just some thoughts.
Also: My robot picks.
Wheeled1:
Trike
Wheeled2:
TeslaTank (because they're robots, and use electricity?)
Wheeled3:
Baneblade
Artillery:
Annihilator (although it's not that portable. At all.)
Animal:
MechJaguar (Oddly enough, we have a robot animal hybrid. I love you guys.)
Air:
The Imperial Sky Armor (Matte black AND propellers? Oh yes.)
Settler: Bebro's
Futuristic Mech units (One could also possibly get a Wheeled out of the recon scout, or an artillery out of the plasma artillery)
Other civs:
The
Ol' Farm Truck would do well for Puritans or pesky Raiders.
My favorites that don't necessarily fit a schema:
Robot B. It's matte black. Classy.
The
Predator, because it has an electrical death, and is matte black. Deadly.
Special mention to the
Energon Cube and the
Energy Elemental. Because robots need ENERGY!
Perhaps deserving of their own race, I hold all of the WH40K units in extremely high regard, but I think the
Tarantula and Leptuos Fortuna are good candidates for a Wheeled1 and Settler, respectively.
The M1
Mech, because it is from RoboCop, and in the movie was entirely robotic.
The
Battlewalker, because it is so awesome.
Odd how those two almost make an upgrade path?
The
Olai robot, which is rather shiny, but oh so simple and useful as a basic unit.
The
Cylon Centurion, for his Stormtrooper styling and attention to military hierarchy.
Oh my, do those upgrade too? Oh well.
I would also work in the
DropPod, as some kind of rapidly deployable or super-special orbiting unit (autoproduced by the RecontactUbermachineFactorySatellite?)
And before anybody gives me an odd glance, followed by some grumbled "WTH is he throwing all this stuff out," I've been unable to allocate enough time for my own modding, and thus this is the first CivIII thinking I've done in a while. Hurrah.
Edit: changed wording of the first suggestion.
Edit2: Added robot suggestions to not double post.