From the various books i had read about Alexander the Great, the sarissa (a long pike) had always been portreyed as the main weapon of his infantry. I always thought it was the battle winner, however in a recent book ive been reading the author makes the point that the Phalanx was and extremely cumbersome and inflexible unit, thats main use was in fact routing the opposition after they had broke. He goes on to say that Alexander in fact ditched the weapon before he invaded india.
Id never really thought about it before but i supose he could be right, though hes the first person whos book id read that made this point.

Any views welcome.

I have always read that his cavalry, was one of his biggest tactical assets (I think he actually had light and heavy cavalry)...this was the key to his defeat of Darius.

My bad...you did write infantry.

the phalanx was battle winners, they served to hold the enemy in place (the enemy on engaging would be trying to get thorough the maze of spears and some clever soldiers would try and get around it) while the cavalry maneouvered, destroyed the enemy calvalry, and then hit the enemy commander and infrantry force from the rear usuallly causing total panic and a total rout. without the defensive capabilitys of the sarissa and phalanx formation, this could not be done becuse the enemy elite infranty would have torn the fairly weaker greek infrantry apart before the cavalry could become effective.