Favorite Units?

[macsen rufus]

Well, I have bit of a soft-spot for hybrids - ranged + melee capable, and I think my favourite of these has to be the Ottoman Infantry. It's a long while since I've played a Turkish campaign so can't recall all the details, but I like the ability to use up the arrows then join the melee in a useful way. I often give the AI a surprise by keeping them in engage at will rather than skirmish, so they can go in the front line at a pinch (though I'm more likely to deploy them behind Saracens until it's time to move them out to the flanks and come in around and behind the pinned enemy.)

One undervalued unit I like for Catholics is the mounted Xbow - unlike HAs it can get quite tough, especially with a bit of valour and some teching up. Indispensible unit for my HRE campaigns - AP missiles and quite respectable medium cav, what more can the Emperor ask

In my current PMTW campaign, I'm developing quite a respect for berber cavalry, as well

[Ayachuco]

The undervalued unit that I like is the very flexible mounted sergeants. They don't suffer the poor morale of the hobilars and due to their quickness are very good at launching coordinated flanking movements with knights. Esp. playing as the English, I use them to harass the Jinettes so they don't mercilessly destroy my very inflexible formation of billmen/longbowmen. They're also perfect for luring those Frenchie knights into my pole troops. Just let them chase my mounted seargants and send my spears toward them and the knights will hit them and then double back the sergeants and hit the knights in the rear. They're also good in sally battles, I just send them out and try to destroy any seige artillery the army brought with them. I usually have one or two in my castle garrisons. They're cheap, quick, and reliable (most of the time).
I may not want them, but I NEED the Mounted Sergeants.

My favourite unique troop is the Naptha Throwers. They're pretty useless on the attack but if they can loose one volley(and that's usually all they throw) its pretty neat to see the explosions wreak havoc on the enemy. Another good choice is the Almohad Urban Militias. I HATE them. Esp. whenever I'm trying to get the almohads out of Granada. All those CMAA defeated at the hands of infidel militia. EVIL...

Finally, you got to love those Katanks.
No need for an explanation...Go Byzantines.

[Alouette]

Vikings: Like MAA except available in early from a fort (hence you get faster armor/weapon upgrades), and their AP. I bet the Mongols were pretty bloody surprised by my Viking horde.

FK's: Vicious enough to flank with, tough enough to flank with more than once.

That's really all you need.