[EricH]

All of them, plus all the options you didn't mention. Why? The game objective changes, so your objective(s) change. Different objectives need different equipment to obtain them. For example, a mecanum system can be good for precise positioning without having to back out, realign, and come back. The six-wheel dropped center design is a good all-around design, but it can have trouble with being easily spun when hit hard (which can be designed around).

Also, could you clarify what you mean by "6 wheel drive system with turning wheels"? I mean, all the wheels in a drive system turn normally; otherwise, the robot doesn't drive... Do you mean a combination of a crab system (all wheels rotate to allow the robot to go sideways without turning) and a six-wheel system, like the Chariot uses?