Either Rome total war or Empire total war.
For me i had the most fun on Rome but my favorite is empire with darth mod. and a clean version Medival.
Medieval Total War
but it doesn't work on my computer
MTW I shall always love you
Medieval Total War by far.
MTW2: Kingdoms for me...well i dont like gunpowder weapons.....
Rome total war because of its easy to use, cavalry charges and really run campaigns!
Medieval 2 because of the wide range of factions, expansions, and long time frame!
ETW because of the cool new set out, proper gunpowder, and colonies!
Rome Total War, because it was my first total war game, i have sentiment for it ^^
It'd have to be either Rome Total War or Medieval 2 Total War, because they are so fun and easy to mod. Although I do prefer Empire TW's layout... Bah! I could never just pick one of the games. They're all awesome in there own way
Rome. None have ever surpassed it, none will. Rome 2 will never be as good as the original; look at Shogun 2 v Shogun.