As the English, my goal is always to start making Billmen. I play the Rock-Paper-Scissors strategy pretty consistently, and I've found that Billmen don't really have a counter unit. I know there are other units out there that can beat them, but they can always at least hold their own for awhile until help arrives. I like an army of Billmen, backed up by vanilla archers (with tons of archers in reserve), a couple units of light cavalry, plus my general (heavy cavalry) to fight the Mongols. I've never seen anything absolutely wipe out a unit of Mongol Heavy Cavalry, or any other heavies, as effortlessly as Billmen.

For the most part, I've always been a good Catholic when it comes to MTW, but right now I'm trying out the Kievans in XL. I'm really starting to like the Voi in early. They are light, fast swordsmen. I don't usually check stats, but in practice they seem to be as fast as Urban Militia with better morale and more killing power.