I was experimenting with a strengthened Carthage recently and found the initial elephant unit very useful. I captured Messana and Syracuse and wiped out a combined Scipii/Julii army for the loss of only one beastie.

Just keep them away from enemy missile troops and aim for a unit behind the one you want to attack. That way the front unit will often reel back into the rear one and they'll both rout - great fun and much trampling!