I'm going to go against what ANYONE says and say it's Hercules, Goliath, Mercs, and Firebat.
Hercules: Transport stuff, if it goes down, stuff doesn't die, and most of all, it can hold up to FOUR Thors
Goliath: Super Marine Purposes, and for super marauders.
Firebat: It's flame is better than the Hellions. Combined with the Hercules, it provides DEVASTATING results.