I look forward to this war.

That said, just because I sometimes enjoy ranting for no real reason I want to talk about Total War, Medieval 2 and the first Rome to be precise. The AI in that game angers me greatly. It has been too may battles where I brought a legion of infantry to dispose of the tiny stacks of enemies on my borders to find that their 'army' was two or three chariots, something that could never actually wound my attackers but sure as hell could outrun them, turning what should have been a five minute melee into half an hour of me trying to split my forces and trap my eneimes before I give up and let it count as an AI victory. And the way the game calculates who has the better odds of victory irks me a great deal.
When the game looks at the two armies it seems they do nothing but count the heads in each crowd and then say the one with the bigger force will win. I am rarely the larger force, and lose with even greater rarity. The computer never seems to consider the units being brought to the battle, or the possible tactics I may employ.

My favorite example of this is a unnamed battle I was in, taking place in the Britannia expansion to Total War Medieval 2. I had next to no units, I think it was... a noble commander with his bodyguard, a unit of spears, a unit of bombards and a unit of proper artillery. I was sitting in one of the small forts littered across Ireland, as I was playing the Irish, and a English army thought to attack, indeed their chasing is why I was held up in the fort. They came at me with thousands. At least four siege towers, as many or more rams and ladders, and to use these tools of war at least two dozen units, ranging from skirmishers to front line spearmen to noble commanders. I held my little rubbish fort, using my guns to blast away their towers, not a single one reached my walls though a few came close. However in time ladders found their way to the far wall of my fort, and a ram was at the gates. I had my infantry meet the enemy coming in from the now broken gate, and for the enemy climbing the wall... I had my bombards blast away at the wall, the AI being completely unable to cope with such a tactic. Their soldiers kept climbing the wall, until the wall fell out from under them. While this was happening I had my commander and his bodyguard charge into the forces slowly pushing against my infantry, and shattered the English dogs.
After this victory I named my nearest city after the English commander who led the attack, I forget his name. The city was then named [insert name here]'s folly. I shall not forget that mighty battle, nor the intelligence, or lack there of, of Total War's AI.
For reference I was playing on normal, perhaps the AI is smarter on hard, who am I to say?