I think possibly there are two different questions being asked here. I believe the OP was asking what your idea of the best stack you could possibly assemble would be, i.e. which would be most effective in battle, irrespective of cost and availability.

There is a separate question to this, which is "what is the most cost-effective stack you could produce, i.e. a stack which although it may ultimately lose the battle to the above stack, would win the war through its abundance and cheapness.

Perhaps we should have two different categories, a "best budget model" stack, and a "best in show" stack. Of course, my favourite stack falls into neither category; it is neither particularly effective, nor is it very cheap. I just like it.

Quote Originally Posted by Galain_Ironhide
You are definately right though. But when you are bored, sometimes creating all same-type stacks can just spice up the game a little.
Agreed, I find sometimes it is fun to take on an enemy army with a totally unsuitable army. Like trying to take on an eastern horse archer army with an all pikemen stack. After all, Alexander did it, so it must be possible.