I will just add on to what the other people have been saying,but thanks aelf for this wonderful guide!
I'm a bit stunned that no one's mentioned the
Vulture. The vulture is an even stronger axeman, perfect for those early rushes. In fact, given that Gilgamesh has vultures for more powerful axe-rushes, protective archers to defend new territorial aquisicions, early and cheap courthouses to push down maintinence, and creative to shore up cultural defense, Gilga seems talior-made for rushing early, and then choosing your victory, whether peacefully or by conquest.
Another UU that's not mentioned often is the
Landsknecht. With 100% vs. both melee and mounted, the landsknecht has little to fear on the medieval batlefield. the only hard counter to it is the crossbowmen, but have some knights tag along to stop that. With Landsknechts, Knights, and trebs, you can rule the land easily and efficiently. The Rauthus will pay all the costs of your war, so you're free to strenghten your economy or attack again. The extra GG's and protective archer will ensure a well-promoted, impregnable attack and defense.
The
Holkan is interesting becuase it is resourceless and immune to first strikes. While it takes a while to get the techs to build it, once you do, archers' big bonus, their first strike, will be mitigated and the city rading that much easier. With the ball court and Expansive, your holdings will have plenty of room to grow so they can work more cottages, and increase your tech rate.
The
Cataphrat is an absolute monster. It has the same attack as a cuirasseurs, which holds the same place that calvary used to hold. Early powerful calvary screams rush. The hippodrome helps with culture and happiness in your newly conquered cities, and Imp means more military instructors.