Here is one method I came across to deal with enemies who have fast, missle cavalry. First, as mentioned earlier set up a nice wall of spearmen and long thin lines of archers. Second, use light cavalry to draw them close to your spear/archer kill zone... walk to within their firing range then run back and stop short of your spears which will put them in range of your stationary archers.

I used this method against the Turks and each and every time they chased after my Hobilars and got peppered with arrows from five units of 60 archers. At the end I finished off nearly five units of Turk archers and all it cost me was 27 Hobilars.

One thing really funny was that as my Hobilars started getting battered they started to rout when they came under fire from the Turks. This encouraged their horsemen to chase me recklessly and all that would happen is that my Hobilars run back to my spearmen and there they'd catch their nerve.