Very good thought experiment. I would choose marijuana over any of the others in a heartbeat. The only exception would be if the driver is not a regular user. In that case, probably the antihistamines.
Cetirizine and fexofenadine (most 2G antihistamines, in fact) have no significant sedative effect.
Anecdotal, but I am very familiar with a counterexample. The sedative effect is not as severe or persistent as with a 1st-generation drug, but it still has a significant effect on this particular individual, if not a statistically significant effect on the general population.