Gaining victory with zero or few casualities states the ultimate policy don´t you think? Therfore, as I posted earlier, I tend to go with artillery/ misssile oriented combos. This is my record as the Macedonians against Romans:

727-0, 572-0, 190-0, 1405-0, 307-0, 945-0, 446-0, 339-0, 2045-0, 950-0, 464-0 = 8390-0, 11 consecutive defensive battles (which helped ;)).

My combo was 4 onagers, 6 archers, 4 heavy cav and mearly 6 phalanx pikemen spread thin in 5 men rows.